S = input()

L = []
for i, s in enumerate(S):
    if s == 'c':
        for j, t in enumerate(S[i+1:]):
            if t == 'w':
                for k, u in enumerate(S[i+j+2:]):
                    if u == 'w':
                        L += [j+k+3]
                        break

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