#!/usr/bin/env python

def main():
    sl = list(input().strip())
    sw = 0
    sw2 = 0
    ans = 0
    res = 200
    tmp = 200
    i = 0
    while i < len(sl):
        s = sl[i]
        if sw == 0 and s == 'c':
            sw = 1
            ans = 1
            i += 1
            continue
        elif s == 'c':
            tmp = min(tmp,i)
            sw2 = 1
        elif sw == 1 and s == 'w':
            sw = 2
        elif sw == 2 and s == 'w':
            ans += 1
            res = min(ans, res)
            i = tmp if sw2 == 1 else i + 1
            tmp = 200
            sw = 0
            sw2 = 0
            continue
        ans += 1
        i += 1

    if res == 200:
        print('-1')
    else:
        print(res)

if __name__ == '__main__':
    main()