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
g1h2
g1h1
a1b1
a1a5
a1a4
a1a3
a1a2
f1d1
f1e1
c1h6
c1g5
c1f4
c1e3
c1d2
e2d1
e2a6
e2b5
e2c4
e2d3
e2h5
e2g4
e2f3
f2f4
f2f3
g3g4
c5c6

## Board State Fen
r2r2k1/p3pp1p/p3b1p1/b1Pn4/8/6P1/1P2BPP1/R1B2RK1 w - - 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
b2b4
b2b3
g1h2
g1h1
a1b1
a1a5
a1a4
a1a3
a1a2
f1d1
f1e1
c1h6
c1g5
c1f4
c1e3
c1d2
e2d1
e2a6
e2b5
e2c4
e2d3
e2h5
e2g4
e2f3
f2f4
f2f3
g3g4
c5c6

## Board State Fen
r2r2k1/p3pp1p/p3b1p1/b1Pn4/8/6P1/1P2BPP1/R1B2RK1 w - - 0 21
assistant
a1a5