# -*- coding: utf-8 -*-

S = input()

l = -1
min_l = 101
state = 0   # 0:c探索中, 1:cセット中, 2:最後のw探索中
for c in S:
    l += 1
    if c == 'c' and state == 0:
        l = 1
        state = 1
    elif c == 'w' and state == 1:
        state = 2
    elif c == 'w' and state == 2:
        state = 0
        min_l = min(min_l, l)

min_l = -1 if min_l==101 else min_l

print(min_l)