s = input()

wnum = 0
w1idx = 0
w2idx = 0
cww = 0
res = len(s) + 1
for i,ss in enumerate(reversed(s)):
    if ss == 'w':
        if wnum == 0:
            w1idx, w2idx = i, i
            wnum = 1
        elif wnum == 1:
            w1idx = i
            wnum += 1
        else:
            w2idx = w1idx
            w1idx = i
    elif ss == 'c':
        if wnum == 2:
            cww = i - w2idx + 1
            res = min(cww, res)
            wnum = 0
if res > len(s):
    res = -1

print(res)