Given the available moves based on the current board state in FEN notation, think carefully about which move would be best, then make that move. Be sure to note your color indicated in the FEN notation before deciding.
## Available Moves
b5b4
a6a5
f7f5
f7f6
g7g5
g7g6
h7h5
h7h6
b8a8
b8b6
b8b7
b8d8
b8c8
e8f8
e8e7
e8d8
e8d7

## Board State Fen
1r2k3/5ppp/p1R5/1p6/8/2P2P2/PP3K1P/8 b - - 1 31
system
You are a chess playing AI.
user
Given the available moves based on the current board state in FEN notation, think carefully about which move would be best, then make that move. Be sure to note your color indicated in the FEN notation before deciding.
## Available Moves
b5b4
a6a5
f7f5
f7f6
g7g5
g7g6
h7h5
h7h6
b8a8
b8b6
b8b7
b8d8
b8c8
e8f8
e8e7
e8d8
e8d7

## Board State Fen
1r2k3/5ppp/p1R5/1p6/8/2P2P2/PP3K1P/8 b - - 1 31
assistant
a6a5