rrr = input() aaa = raw_input() bbb = raw_input() ans = 0 for i in range(len(aaa)): if aaa[i] != bbb[i]: ans = ans + 1 print ans rrr = input() aaa = raw_input() bbb = raw_input() ans = 0 for i in range(len(aaa)): if aaa[i] != bbb[i]: ans = ans + 1 print ans