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
a7e3
a7d4
a7c5
a7b6
a7b8
b3a5
b3c1
b3c5
b3d2
b3d4
c3c4
g1h1
g1g2
f4f5
f1b1
f1c1
f1d1
f1e1
a4b5
a4a5
h2h4
h2h3
f2f3
a1e1
a1d1
a1c1
a1b1
a1a3
a1a2

## Board State Fen
r1r3k1/Bp1b2bp/6p1/1n6/P3pP2/1NP5/1P3P1P/R4RK1 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
a7e3
a7d4
a7c5
a7b6
a7b8
b3a5
b3c1
b3c5
b3d2
b3d4
c3c4
g1h1
g1g2
f4f5
f1b1
f1c1
f1d1
f1e1
a4b5
a4a5
h2h4
h2h3
f2f3
a1e1
a1d1
a1c1
a1b1
a1a3
a1a2

## Board State Fen
r1r3k1/Bp1b2bp/6p1/1n6/P3pP2/1NP5/1P3P1P/R4RK1 w - - 0 21
assistant
a4b5