def iscww(S):
    N = len(S)
    cww = "cww"
    cnt = 0
    for i in range(N):
        if S[i] == cww[cnt]:
            cnt += 1
            if cnt == 3:
                break
    return cnt == 3

S = input()
ans = 1000
for l in range(len(S)):
    for r in range(l + 1, len(S) + 1):
        if iscww(S[l:r]):
            ans = min(ans, r - l)
if ans == 1000:
    print(-1)
else:
    print(ans)