# No.345 最小チワワ問題
import sys

s = input()

index_c = 0
index_w = 0
count_w = 0
length = sys.maxsize

for i in range(len(s)):
    if s[i] == 'c' and index_c == 0:
        index_c = i
        count_w = 0
    elif s[i] == 'w' and i > index_c:
        index_w = i
        count_w += 1
        if count_w == 2:
            length = min(length, index_w - index_c + 1)

print(length if length != sys.maxsize else -1)