s = input()
N = len(s)

mi = N + 1
for i in range(N):
    if s[i] == 'c':
        cnt = 0
        for j in range(i+1, N):
            if s[j] == 'w':
                cnt += 1
            if cnt >= 2:
                mi = min(mi, j - i + 1)
                break

if mi != N + 1:
    print(mi)
else:
    print(-1)