54321
Remember, for this challenge, there might be more than one valid output.
1 to C 2 to B 1 to B 3 to C 1 to A 2 to C 1 to C 4 to B 1 to B 2 to A 1 to A 3 to B 1 to C 2 to B 1 to B 5 to C 1 to A 2 to C 1 to C 3 to A 1 to B 2 to A 1 to A 4 to C 1 to C 2 to B 1 to B 3 to C 1 to A 2 to C 1 to C