S = input()
s = len(S)

L = []
for i in range(s):
    if S[i] == 'c':
        for j in range(i+1, s):
            if S[j] == 'w':
                for k in range(j+1, s):
                    if S[k] == 'w':
                        L += [k - i + 1]
                        break

print(min(L) if len(L) != 0 else -1)