-module('Main').
-export([main/1]).

main(_) ->
    {ok, [S, T]} = io:fread("", "~s ~s"),
    C = count_difference(S, T),
    io:format("~p~n", [C]),
    halt().

count_difference(S, T) ->
    count_difference(S, T, 0).
count_difference([], [], C) ->
    C;
count_difference([SH|ST], [TH|TT], C) ->
    case SH /= TH of
        true ->
            count_difference(ST, TT, C + 1);
        false ->
            count_difference(ST, TT, C)
    end.

