S = input()

N = len(S)

ans = N + 1
for i in range(N):
    for j in range(i + 1, N + 1):
        T = S[i:j]
        try:
            idx = T.index("c")
            idx = T.index("w", idx + 1)
            T.index("w", idx + 1)
            ans = min(ans, len(T))
        except:
            continue

if ans == N + 1:
    print(-1)
else:
    print(ans)