from Queue import * # Queue, LifoQueue, PriorityQueue
from bisect import * #bisect, insort
from collections import * #deque, Counter,OrderedDict,defaultdict
#set([]) 
import math
import copy
import itertools
import string
import sys
myread = lambda : map(int,raw_input().split())
def solver():
    S = raw_input()
    c = []
    w = []
    for i in xrange(len(S)):
        if S[i] == 'w':
            w.append(i)
        elif S[i] == 'c':
            c.append(i)
    if len(w) < 2 or len(c) < 1:
        print -1
        return
    ans = 10000
    j = 0
    for x in c:
        while j < len(w) and w[j] < x:
            j += 1
        if j + 1 >= len(w):
            break
        ans = min(ans, w[j+1] - x + 1)

    if ans == 10000:
        print -1
    else:
        print ans

        
if __name__ == "__main__":
    solver()