aoc2017day01

import sys

def doit(input):
    q = list(map(int, input.strip()))
    sum = 0
    for i in range(len(q)):
        if q[i] == q[(i+1)%len(q)]:
            sum += q[i]
    return "%d" % sum

input = sys.stdin.read()
print(doit(input))