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
b5b3
b5b4
b5c5
b5b8
b5b7
b5b6
g7g5
g7g6
f7f5
f7f6
e6e5
h7h5
h7h6
d6c4
d6c8
d6e4
d6b7
d6f5
a5a4
a8a6
a8a7
a8d8
a8c8
a8b8
e8c6
e8d7
g8h8
g8f8

## Board State Fen
r3b1k1/5ppp/3np3/pr1p4/3P4/1P1NPP2/3N2PP/R1R3K1 b - - 0 21
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
b5b3
b5b4
b5c5
b5b8
b5b7
b5b6
g7g5
g7g6
f7f5
f7f6
e6e5
h7h5
h7h6
d6c4
d6c8
d6e4
d6b7
d6f5
a5a4
a8a6
a8a7
a8d8
a8c8
a8b8
e8c6
e8d7
g8h8
g8f8

## Board State Fen
r3b1k1/5ppp/3np3/pr1p4/3P4/1P1NPP2/3N2PP/R1R3K1 b - - 0 21
assistant
b5b8