#!/usr/bin/env python3
import re

lines = (x.strip() for x in open("input.txt"))

for line in lines:
    regex = r"(\w)" + "".join("(?!" + "|".join("\\{0}".format(j) for j in range(1, i+2)) + r")(\w)" for i in range(13))
    print(re.search(regex, line).end())