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
b5a6
b5a5
b5a4
b6a4
b6a8
b6c4
b6c8
b6d5
b6d7

## Board State Fen
8/2R5/1n6/1k6/3K4/8/8/8 b - - 1 58
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
b5a6
b5a5
b5a4
b6a4
b6a8
b6c4
b6c8
b6d5
b6d7

## Board State Fen
8/2R5/1n6/1k6/3K4/8/8/8 b - - 1 58
assistant
b6a4