s = input()

res = len(s) + 1
for i,ss in enumerate(s):
    if ss != 'c':
        continue
    w = 0
    for j in range(i + 1, len(s)):
        if s[j] == 'w':
            w += 1
        elif s[j] == 'c':
            break
        if w == 2:
            cww = j - i + 1
            res = min(cww, res)
            break
if res > len(s):
    res = -1

print(res)