from bisect import bisect_left
S = input()
N = len(S)
cnt_w = [0]*N
for i, s in enumerate(S):
    if s == 'w':
        cnt_w[i] = 1
for i in range(1, N):
    cnt_w[i] += cnt_w[i - 1]

ans = N + 1
for i in range(N):
    if S[i] == 'c':
        # cnt_w[i] + 2 が一番最初に出てくるマスは？
        r_idx = bisect_left(cnt_w, cnt_w[i] + 2)
        if r_idx <= N - 1:
            sub = r_idx - i + 1
            if sub < ans:
                ans = sub
if ans == N + 1:
    ans = -1
print(ans)