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
b2b4
b2b3
h1f1
h1g1
h1h3
h1h2
e1g1
e1f1
e1d2
f2f4
f2f3
a3a4
c3a5
c3b4
c3d2
c3g7
c3f6
c3e5
c3d4
e3e4
h4h5
a8g2
a8f3
a8e4
a8d5
a8c6
a8b7

## Board State Fen
B3rbk1/p1p2ppp/8/8/6bP/P1B1P3/1P3P2/4K2R w K - 1 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
b2b4
b2b3
h1f1
h1g1
h1h3
h1h2
e1g1
e1f1
e1d2
f2f4
f2f3
a3a4
c3a5
c3b4
c3d2
c3g7
c3f6
c3e5
c3d4
e3e4
h4h5
a8g2
a8f3
a8e4
a8d5
a8c6
a8b7

## Board State Fen
B3rbk1/p1p2ppp/8/8/6bP/P1B1P3/1P3P2/4K2R w K - 1 21
assistant
a8d5