-module(day6).

-export([solve/1]).

solve(InputData) ->
	{solve(InputData, 1), none}.

solve(<<A, A, Rest/binary>>, N) -> solve(<<A, Rest/binary>>, N+1);
solve(<<A, B, A, Rest/binary>>, N) -> solve(<<B, A, Rest/binary>>, N+1);
solve(<<A, B, C, A, Rest/binary>>, N) -> solve(<<B, C, A, Rest/binary>>, N+1);
solve(<<A, B, B, Rest/binary>>, N) -> solve(<<B, Rest/binary>>, N+2);
solve(<<A, B, C, C, Rest/binary>>, N) -> solve(<<C, Rest/binary>>, N+3);
solve(<<A, B, C, D, _Rest/binary>>, N) when A /= B andalso B /= C andalso C /= D andalso
					    A /= C andalso B /= D andalso A /= D -> N+3;
solve(<<_, Rest/binary>>, N) -> solve(Rest, N+1).