# 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':
        index_c = i
        count_w = 0

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

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