def cww(s):
    for i, c in enumerate(s):
        if c == 'c':
            yield i

S = input()
ans = 101
for idx in cww(S):
    flag = False
    cnt = 0
    for c in S[idx:]:
        cnt += 1
        if c == 'w':
            if flag:
                ans = min(ans, cnt)
                break
            else:
                flag = True
if ans == 101:
    ans = -1
print(ans)