SpaceChem Bench: No Thanks Necessary

sensing_5 Medium Multi-reactor production Multi-reactor Alkonost Random inputs · SpaceChem Bench report →

Random inputs: α Nitrogen (N2) / Oxygen (O2), β Water (H2O) / Sodium Chloride (NaCl). Output: ψ Nitric Acid (HNO3) ×5, ω Sodium Nitrate (NaNO3) ×5. Features: Max reactors: 5, Recycler, Random inputs.

In SpaceChem Bench, 16 LLMs each had one attempt at this SpaceChem puzzle, with 40 minutes to build a working solution and keep optimizing it, without seeing the community archive. 6 of 16 models solved it. No model found a new Pareto-frontier point beyond the frozen community archive.

6 / 16models solved it
2,106best LLM cycles (782 community)
0new frontier points

Records

ScoreCommunity bestBest LLMModel
Cycles7822,106GPT-6 Astra · +169%
Reactors23Gemini 4 Argon · +50%
Symbols4177GPT-6 Astra · +88%

Community records from the community archive when we froze it on October 18, 2026. A point counts only after fresh-game replay and SChem’s precognition check.

Pareto frontier

Pareto explorer

Lower is better ↙
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Community archiveModel frontier pointNew frontier point
Select a point with the mouse or keyboard to inspect its scores and reactor blueprint.

Search over time

Loading puzzle trajectories…

Every model

ModelSolvedBest cyclesBest reactorsBest symbolsNew frontier points
01GPT-6 AstraYes2,106477—
02Opus 5.5Yes2,128495—
03GPT-6.1 SolYes3,024499—
04Fable 5.1Yes4,7664150—
05Sonnet 5.5Yes6,7944102—
06Gemini 4 ArgonYes6,9583101—
07DeepSeek V4.1 FlashNo————
08GLM-5.3No————
09GPT-6 LunaNo————
10Gemini 3.8 FlashNo————
11Grok 4.7No————
12Haiku 5.5No————
13Kimi K3.1 ProNo————
14MiMo-V2.6-ProNo————
15Muse Spark 1.3No————
16Muse Wonder 1.0No————

Best scores can come from different solutions. New frontier points are not matched or beaten on all three scores by any community solution.

Best model solutions

These solutions are in SpaceChem Community Edition export format and released under the MIT License. All of this puzzle’s model solutions are on GitHub and Hugging Face.

GPT-6 Astra Fewest cyclesFewest symbols

2,106 cycles · 4 reactors · 77 symbolssensing_5.2106-4-77.txt on GitHub

Layout (Reactor 1 of 4)

α β ψ ω 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 → → ← ↑ → ← S↓ B− S← IN α GRAB OUT ψ ?O↓ DROP OUT ω DROP B−

Running in the game

GPT-6 Astra solution running on sensing_5 in SpaceChem
SpaceChem Community Edition export (sensing_5.2106-4-77.txt)
SOLUTION:No Thanks Necessary,Player,0-0-0
COMPONENT:'drag-advanced-reactor',8,4,''
MEMBER:'instr-start',90,0,128,0,0,0,0
MEMBER:'instr-start',180,0,32,2,0,0,0
MEMBER:'feature-bonder',-1,0,1,6,1,0,0
MEMBER:'feature-bonder',-1,0,1,7,1,0,0
MEMBER:'feature-bonder',-1,0,1,6,4,0,0
MEMBER:'feature-bonder',-1,0,1,7,4,0,0
MEMBER:'feature-sensor',-1,0,1,5,1,0,0
MEMBER:'instr-arrow',0,0,64,0,1,0,0
MEMBER:'instr-arrow',0,0,64,5,4,0,0
MEMBER:'instr-arrow',180,0,64,6,1,0,0
MEMBER:'instr-arrow',-90,0,64,6,4,0,0
MEMBER:'instr-input',-1,0,128,0,1,0,0
MEMBER:'instr-grab',-1,1,128,1,1,0,0
MEMBER:'instr-output',-1,0,128,3,1,0,0
MEMBER:'instr-sensor',90,0,128,5,1,0,8
MEMBER:'instr-grab',-1,2,128,6,1,0,0
MEMBER:'instr-output',-1,1,128,6,2,0,0
MEMBER:'instr-grab',-1,2,128,6,4,0,0
MEMBER:'instr-arrow',0,0,16,0,0,0,0
MEMBER:'instr-arrow',180,0,16,1,0,0,0
MEMBER:'instr-bond',-1,1,32,0,0,0,0
MEMBER:'instr-bond',-1,1,32,1,0,0,0
PIPE:0,4,1
PIPE:0,4,0
PIPE:0,4,-1
PIPE:0,4,-2
PIPE:0,5,-2
PIPE:0,6,-2
PIPE:0,6,-1
PIPE:0,6,0
PIPE:0,6,1
PIPE:1,4,2
PIPE:1,5,2
PIPE:1,5,3
PIPE:1,5,4
PIPE:1,5,5
PIPE:1,5,6
PIPE:1,5,7
PIPE:1,6,7
PIPE:1,6,6
PIPE:1,6,5
PIPE:1,6,4
PIPE:1,6,3
PIPE:1,6,2
COMPONENT:'drag-advanced-reactor',11,17,''
MEMBER:'instr-start',90,0,128,0,0,0,0
MEMBER:'instr-start',0,0,32,0,7,0,0
MEMBER:'feature-bonder',-1,0,1,7,3,0,0
MEMBER:'feature-bonder',-1,0,1,7,4,0,0
MEMBER:'feature-sensor',-1,0,1,9,7,0,0
MEMBER:'feature-bonder',-1,0,1,0,7,0,0
MEMBER:'feature-bonder',-1,0,1,4,7,0,0
MEMBER:'instr-arrow',0,0,64,0,1,0,0
MEMBER:'instr-arrow',-90,0,64,0,3,0,0
MEMBER:'instr-arrow',90,0,64,7,1,0,0
MEMBER:'instr-arrow',180,0,64,7,3,0,0
MEMBER:'instr-input',-1,0,128,0,1,0,0
MEMBER:'instr-grab',-1,1,128,1,1,0,0
MEMBER:'instr-rotate',-1,0,128,2,1,0,0
MEMBER:'instr-output',-1,1,128,4,3,0,0
MEMBER:'instr-output',-1,0,128,5,3,0,0
MEMBER:'instr-bond',-1,1,128,6,3,0,0
MEMBER:'instr-grab',-1,2,128,7,3,0,0
PIPE:0,4,1
PIPE:0,5,1
PIPE:0,6,1
PIPE:0,7,1
PIPE:0,7,0
PIPE:0,7,-1
PIPE:0,7,-2
PIPE:0,7,-3
PIPE:0,7,-4
PIPE:0,8,-4
PIPE:0,9,-4
PIPE:1,4,2
PIPE:1,5,2
PIPE:1,6,2
PIPE:1,7,2
PIPE:1,8,2
PIPE:1,9,2
PIPE:1,9,3
PIPE:1,10,3
PIPE:1,11,3
PIPE:1,12,3
PIPE:1,13,3
PIPE:1,14,3
PIPE:1,15,3
PIPE:1,15,2
PIPE:1,15,1
PIPE:1,15,0
PIPE:1,15,-1
PIPE:1,15,-2
PIPE:1,15,-3
PIPE:1,15,-4
PIPE:1,15,-5
PIPE:1,15,-6
PIPE:1,15,-7
PIPE:1,15,-8
PIPE:1,15,-9
PIPE:1,15,-10
PIPE:1,15,-11
PIPE:1,14,-11
PIPE:1,14,-12
PIPE:1,14,-13
COMPONENT:'drag-advanced-reactor',15,4,''
MEMBER:'instr-start',180,0,128,8,0,0,0
MEMBER:'instr-start',90,0,32,0,2,0,0
MEMBER:'feature-bonder',-1,0,1,2,3,0,0
MEMBER:'feature-bonder',-1,0,1,2,4,0,0
MEMBER:'feature-bonder',-1,0,1,2,2,0,0
MEMBER:'feature-sensor',-1,0,1,4,2,0,0
MEMBER:'feature-bonder',-1,0,1,0,7,0,0
MEMBER:'instr-arrow',90,0,64,0,0,0,0
MEMBER:'instr-arrow',0,0,64,0,1,0,0
MEMBER:'instr-arrow',90,0,64,2,1,0,0
MEMBER:'instr-arrow',90,0,64,2,2,0,0
MEMBER:'instr-arrow',0,0,64,2,3,0,0
MEMBER:'instr-arrow',180,0,64,3,2,0,0
MEMBER:'instr-arrow',-90,0,64,3,3,0,0
MEMBER:'instr-arrow',180,0,64,7,0,0,0
MEMBER:'instr-arrow',-90,0,64,7,2,0,0
MEMBER:'instr-input',-1,0,128,0,0,0,0
MEMBER:'instr-grab',-1,1,128,0,1,0,0
MEMBER:'instr-grab',-1,1,128,1,1,0,0
MEMBER:'instr-sync',-1,0,128,2,2,0,0
MEMBER:'instr-bond',-1,0,128,2,3,0,0
MEMBER:'instr-sensor',0,0,128,3,2,0,8
MEMBER:'instr-rotate',-1,0,128,3,3,0,0
MEMBER:'instr-output',-1,0,128,7,0,0,0
MEMBER:'instr-grab',-1,2,128,7,2,0,0
MEMBER:'instr-arrow',90,0,16,0,3,0,0
MEMBER:'instr-arrow',0,0,16,0,4,0,0
MEMBER:'instr-arrow',180,0,16,2,3,0,0
MEMBER:'instr-arrow',-90,0,16,2,4,0,0
MEMBER:'instr-input',-1,1,32,0,3,0,0
MEMBER:'instr-grab',-1,1,32,0,4,0,0
MEMBER:'instr-grab',-1,1,32,1,4,0,0
MEMBER:'instr-sync',-1,0,32,2,3,0,0
MEMBER:'instr-grab',-1,2,32,2,4,0,0
PIPE:0,4,1
PIPE:0,5,1
PIPE:0,5,2
PIPE:0,5,3
PIPE:0,5,4
PIPE:0,5,5
PIPE:0,5,6
PIPE:0,5,7
PIPE:0,5,8
PIPE:1,4,2
COMPONENT:'drag-advanced-reactor',21,11,''
MEMBER:'instr-start',-90,0,128,0,4,0,0
MEMBER:'instr-start',90,0,32,0,6,0,0
MEMBER:'feature-bonder',-1,0,1,4,2,0,0
MEMBER:'feature-bonder',-1,0,1,4,3,0,0
MEMBER:'feature-sensor',-1,0,1,5,3,0,0
MEMBER:'feature-bonder',-1,0,1,0,7,0,0
MEMBER:'feature-bonder',-1,0,1,9,7,0,0
MEMBER:'instr-arrow',0,0,64,0,2,0,0
MEMBER:'instr-arrow',-90,0,64,0,3,0,0
MEMBER:'instr-arrow',0,0,64,6,5,0,0
MEMBER:'instr-arrow',90,0,64,7,2,0,0
MEMBER:'instr-arrow',180,0,64,7,3,0,0
MEMBER:'instr-arrow',180,0,64,8,3,0,0
MEMBER:'instr-arrow',-90,0,64,8,5,0,0
MEMBER:'instr-input',-1,0,128,0,2,0,0
MEMBER:'instr-grab',-1,1,128,1,2,0,0
MEMBER:'instr-sync',-1,0,128,4,2,0,0
MEMBER:'instr-bond',-1,0,128,5,2,0,0
MEMBER:'instr-sensor',90,0,128,6,2,0,11
MEMBER:'instr-grab',-1,2,128,7,2,0,0
MEMBER:'instr-output',-1,0,128,7,3,0,0
MEMBER:'instr-grab',-1,2,128,7,5,0,0
MEMBER:'instr-output',-1,1,128,8,5,0,0
MEMBER:'instr-arrow',90,0,16,0,2,0,0
MEMBER:'instr-arrow',0,0,16,0,7,0,0
MEMBER:'instr-arrow',180,0,16,4,2,0,0
MEMBER:'instr-arrow',-90,0,16,4,7,0,0
MEMBER:'instr-input',-1,1,32,0,7,0,0
MEMBER:'instr-grab',-1,1,32,1,7,0,0
MEMBER:'instr-sync',-1,0,32,4,2,0,0
MEMBER:'instr-grab',-1,2,32,4,3,0,0
PIPE:0,4,1
PIPE:0,4,0
PIPE:0,4,-1
PIPE:0,3,-1
PIPE:0,2,-1
PIPE:0,1,-1
PIPE:0,0,-1
PIPE:0,0,-2
PIPE:0,0,-3
PIPE:1,4,2
PIPE:1,4,3
PIPE:1,4,4
PIPE:1,3,4
PIPE:1,2,4
PIPE:1,1,4
PIPE:1,0,4
PIPE:1,-1,4
PIPE:1,-1,5
PIPE:1,-1,6
PIPE:1,-1,7
COMPONENT:'drag-atmospheric-input',4,5,''
PIPE:0,2,0
PIPE:0,3,0
COMPONENT:'drag-oceanic-input',7,18,''
PIPE:0,2,0
PIPE:0,3,0

Gemini 4 Argon Fewest reactors

6,958 cycles · 3 reactors · 101 symbolssensing_5.6958-3-101.txt on GitHub

Layout (Reactor 1 of 3)

α β ψ ω 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 → ↑ ↓ → ↓ → ↓ ← → ↑ ↓ → ↓ → ← ↑ ↑ ← ↓ ↑ ← ↓ S↑ S← IN α IN α G/D G/D SYNC ?O→ ?N→ SYNC B− SYNC B− B− SYNC B− B− OUT ψ OUT ψ SYNC OUT ψ OUT ψ G/D G/D SYNC G/D G/D OUT ω SYNC SYNC OUT ω

Running in the game

Gemini 4 Argon solution running on sensing_5 in SpaceChem
SpaceChem Community Edition export (sensing_5.6958-3-101.txt)
SOLUTION:No Thanks Necessary,Player,0-0-0
COMPONENT:'drag-advanced-reactor',10,5,''
MEMBER:'instr-start',-90,0,128,0,2,0,0
MEMBER:'instr-start',180,0,32,1,4,0,0
MEMBER:'feature-bonder',-1,0,1,3,2,0,0
MEMBER:'feature-bonder',-1,0,1,4,2,0,0
MEMBER:'feature-bonder',-1,0,1,5,2,0,0
MEMBER:'feature-bonder',-1,0,1,6,2,0,0
MEMBER:'feature-sensor',-1,0,1,3,1,0,0
MEMBER:'instr-arrow',0,0,64,0,1,0,0
MEMBER:'instr-arrow',-90,0,64,0,6,0,0
MEMBER:'instr-arrow',90,0,64,2,1,0,0
MEMBER:'instr-arrow',0,0,64,2,2,0,0
MEMBER:'instr-arrow',90,0,64,5,2,0,0
MEMBER:'instr-arrow',0,0,64,5,5,0,0
MEMBER:'instr-arrow',90,0,64,7,5,0,0
MEMBER:'instr-arrow',180,0,64,7,6,0,0
MEMBER:'instr-input',-1,0,128,0,1,0,0
MEMBER:'instr-grab',-1,0,128,1,1,0,0
MEMBER:'instr-sync',-1,0,128,1,6,0,0
MEMBER:'instr-sensor',0,0,128,2,1,0,8
MEMBER:'instr-sync',-1,0,128,2,6,0,0
MEMBER:'instr-bond',-1,1,128,3,2,0,0
MEMBER:'instr-sync',-1,0,128,3,6,0,0
MEMBER:'instr-bond',-1,1,128,4,2,0,0
MEMBER:'instr-sync',-1,0,128,4,6,0,0
MEMBER:'instr-bond',-1,1,128,5,2,0,0
MEMBER:'instr-output',-1,0,128,5,3,0,0
MEMBER:'instr-sync',-1,0,128,5,6,0,0
MEMBER:'instr-output',-1,0,128,6,0,0,0
MEMBER:'instr-grab',-1,0,128,6,1,0,0
MEMBER:'instr-sync',-1,0,128,6,6,0,0
MEMBER:'instr-grab',-1,0,128,7,5,0,0
MEMBER:'instr-output',-1,1,128,7,6,0,0
MEMBER:'instr-arrow',0,0,16,0,1,0,0
MEMBER:'instr-arrow',-90,0,16,0,4,0,0
MEMBER:'instr-arrow',90,0,16,2,1,0,0
MEMBER:'instr-arrow',0,0,16,2,2,0,0
MEMBER:'instr-arrow',90,0,16,5,2,0,0
MEMBER:'instr-arrow',0,0,16,5,5,0,0
MEMBER:'instr-arrow',180,0,16,7,4,0,0
MEMBER:'instr-arrow',-90,0,16,7,5,0,0
MEMBER:'instr-input',-1,0,32,0,1,0,0
MEMBER:'instr-sync',-1,0,32,0,4,0,0
MEMBER:'instr-grab',-1,0,32,1,1,0,0
MEMBER:'instr-sensor',0,0,32,2,1,0,7
MEMBER:'instr-bond',-1,1,32,4,2,0,0
MEMBER:'instr-bond',-1,1,32,5,2,0,0
MEMBER:'instr-output',-1,0,32,5,3,0,0
MEMBER:'instr-output',-1,0,32,6,0,0,0
MEMBER:'instr-grab',-1,0,32,6,1,0,0
MEMBER:'instr-sync',-1,0,32,6,4,0,0
MEMBER:'instr-output',-1,1,32,7,4,0,0
MEMBER:'instr-grab',-1,0,32,7,5,0,0
MEMBER:'instr-arrow',-90,0,64,6,1,0,0
MEMBER:'instr-arrow',180,0,64,6,0,0,0
MEMBER:'instr-arrow',90,0,64,0,0,0,0
MEMBER:'instr-arrow',-90,0,16,6,1,0,0
MEMBER:'instr-arrow',180,0,16,6,0,0,0
MEMBER:'instr-arrow',90,0,16,0,0,0,0
PIPE:0,4,1
PIPE:0,5,1
PIPE:0,5,0
PIPE:0,5,-1
PIPE:0,5,-2
PIPE:0,5,-3
PIPE:0,6,-3
PIPE:0,7,-3
PIPE:0,8,-3
PIPE:0,9,-3
PIPE:0,10,-3
PIPE:0,11,-3
PIPE:0,12,-3
PIPE:0,13,-3
PIPE:0,14,-3
PIPE:0,15,-3
PIPE:1,4,2
PIPE:1,4,3
PIPE:1,4,4
PIPE:1,4,5
PIPE:1,4,6
PIPE:1,4,7
PIPE:1,5,7
COMPONENT:'drag-atmospheric-input',4,5,''
PIPE:0,2,0
PIPE:0,3,0
PIPE:0,4,0
PIPE:0,5,0
PIPE:0,5,1
COMPONENT:'drag-advanced-reactor',10,16,''
MEMBER:'instr-start',180,0,128,3,0,0,0
MEMBER:'instr-start',180,0,32,4,6,0,0
MEMBER:'feature-bonder',-1,0,1,5,4,0,0
MEMBER:'feature-bonder',-1,0,1,6,4,0,0
MEMBER:'feature-bonder',-1,0,1,0,7,0,0
MEMBER:'feature-bonder',-1,0,1,9,7,0,0
MEMBER:'feature-sensor',-1,0,1,4,7,0,0
MEMBER:'instr-arrow',90,0,64,1,0,0,0
MEMBER:'instr-arrow',0,0,64,1,4,0,0
MEMBER:'instr-arrow',0,0,64,5,1,0,0
MEMBER:'instr-arrow',-90,0,64,5,4,0,0
MEMBER:'instr-arrow',180,0,64,7,0,0,0
MEMBER:'instr-arrow',-90,0,64,7,1,0,0
MEMBER:'instr-grab',-1,0,128,1,1,0,0
MEMBER:'instr-input',-1,0,128,2,0,0,0
MEMBER:'instr-output',-1,1,128,5,3,0,0
MEMBER:'instr-bond',-1,1,128,5,4,0,0
MEMBER:'instr-output',-1,0,128,7,0,0,0
MEMBER:'instr-grab',-1,0,128,7,1,0,0
PIPE:0,4,1
PIPE:0,5,1
PIPE:0,5,0
PIPE:0,5,-1
PIPE:0,5,-2
PIPE:0,5,-3
PIPE:1,4,2
PIPE:1,5,2
PIPE:1,6,2
PIPE:1,7,2
PIPE:1,8,2
PIPE:1,9,2
PIPE:1,9,3
PIPE:1,10,3
PIPE:1,10,4
PIPE:1,11,4
PIPE:1,12,4
PIPE:1,13,4
PIPE:1,14,4
PIPE:1,15,4
PIPE:1,15,3
PIPE:1,15,2
PIPE:1,15,1
PIPE:1,15,0
PIPE:1,15,-1
PIPE:1,15,-2
PIPE:1,15,-3
PIPE:1,15,-4
PIPE:1,15,-5
PIPE:1,15,-6
PIPE:1,15,-7
PIPE:1,15,-8
PIPE:1,15,-9
PIPE:1,15,-10
PIPE:1,15,-11
PIPE:1,15,-12
COMPONENT:'drag-advanced-reactor',16,11,''
MEMBER:'instr-start',-90,0,128,0,2,0,0
MEMBER:'instr-start',90,0,32,0,4,0,0
MEMBER:'feature-bonder',-1,0,1,1,1,0,0
MEMBER:'feature-bonder',-1,0,1,2,1,0,0
MEMBER:'feature-bonder',-1,0,1,3,1,0,0
MEMBER:'feature-bonder',-1,0,1,3,2,0,0
MEMBER:'feature-sensor',-1,0,1,4,1,0,0
MEMBER:'instr-arrow',0,0,64,0,1,0,0
MEMBER:'instr-arrow',-90,0,64,0,6,0,0
MEMBER:'instr-arrow',0,0,64,1,0,0,0
MEMBER:'instr-arrow',-90,0,64,1,1,0,0
MEMBER:'instr-arrow',90,0,64,2,0,0,0
MEMBER:'instr-arrow',0,0,64,2,1,0,0
MEMBER:'instr-arrow',0,0,64,3,2,0,0
MEMBER:'instr-arrow',0,0,64,4,0,0,0
MEMBER:'instr-arrow',-90,0,64,4,2,0,0
MEMBER:'instr-arrow',90,0,64,7,0,0,0
MEMBER:'instr-arrow',180,0,64,7,6,0,0
MEMBER:'instr-input',-1,0,128,0,1,0,0
MEMBER:'instr-grab',-1,0,128,1,1,0,0
MEMBER:'instr-input',-1,0,128,2,0,0,0
MEMBER:'instr-bond',-1,0,128,2,1,0,0
MEMBER:'instr-rotate',-1,1,128,3,0,0,0
MEMBER:'instr-sensor',90,0,128,3,1,0,8
MEMBER:'instr-sync',-1,0,128,3,2,0,0
MEMBER:'instr-bond',-1,0,128,4,1,0,0
MEMBER:'instr-sensor',90,0,128,5,0,0,11
MEMBER:'instr-grab',-1,0,128,7,0,0,0
MEMBER:'instr-output',-1,0,128,7,1,0,0
MEMBER:'instr-grab',-1,0,128,7,5,0,0
MEMBER:'instr-output',-1,1,128,7,6,0,0
MEMBER:'instr-arrow',90,0,16,0,2,0,0
MEMBER:'instr-arrow',0,0,16,0,5,0,0
MEMBER:'instr-arrow',0,0,16,1,3,0,0
MEMBER:'instr-arrow',-90,0,16,1,5,0,0
MEMBER:'instr-arrow',180,0,16,3,2,0,0
MEMBER:'instr-arrow',-90,0,16,3,3,0,0
MEMBER:'instr-input',-1,1,32,0,5,0,0
MEMBER:'instr-grab',-1,0,32,1,5,0,0
MEMBER:'instr-sync',-1,0,32,2,3,0,0
MEMBER:'instr-grab',-1,0,32,3,2,0,0
MEMBER:'instr-arrow',-90,0,64,3,1,0,0
MEMBER:'instr-arrow',180,0,64,3,0,0,0
MEMBER:'instr-arrow',0,0,64,5,5,0,0
MEMBER:'instr-arrow',90,0,64,7,5,0,0
PIPE:0,4,1
PIPE:0,5,1
PIPE:0,5,0
PIPE:0,5,-1
PIPE:0,5,-2
PIPE:0,5,-3
PIPE:1,4,2
PIPE:1,4,3
PIPE:1,4,4
PIPE:1,4,5
PIPE:1,4,6
PIPE:1,4,7
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