S = input()

ans = None
for i in range(len(S)):
    if S[i] == 'c':
        f = 0
        for j in range(i+1, len(S)):
            if f == 0 and S[j] == 'w':
                f += 1
            elif f == 1 and S[j] == 'w':
                if ans is None:
                    ans = j - i + 1
                else:
                    ans = min(ans, j - i + 1)
                break
print([ans, -1][ans is None])