#!/usr/bin/env python3
#fileencoding: utf-8

count = 0
mi = 100
w_cnt = 0
start = 0
mi_start = 0
mi_end = 0
cww = False
S = input()
for idx,i in enumerate(S):
    if count == 0 and i == "c":
        count += 1
        start = idx
    elif count >= 1 and i == "w":
        w_cnt += 1
        count += 1
        if w_cnt >= 2:
            cww = True
            if mi > count:
                mi = count
                mi_start = start
                mi_end = idx+1
            count = 0
            w_cnt = 0
    else:
        if count >= 1:
            count += 1
        else:
            count = 0

if cww is False:
    print(-1)
else:
    s = S[mi_start:mi_end]
    count = 0
    w_cnt = 0
    for i in s[::-1]:
        if i == "w":
            count += 1
            w_cnt += 1
        elif w_cnt >= 2 and i == "c":
            cww = True
            count += 1
            if mi > count:
                mi = count
            count = 0
            w_cnt = 0
        else:
            if count >= 1:
                count += 1
            else:
                count = 0
    print(mi)