S = input()

N = len(S)
cww_len = []
for i in range(N):
    if S[i] == "c":
        cww_found = False
        for j in range(i+1, N):
            if S[j] == "w":
                for k in range(j+1, N):
                    if S[k] == "w":
                        cww = k - i + 1
                        cww_len.append(cww)
                        cww_found = True
                        break
                if cww_found:
                    break

if len(cww_len) == 0:
    print(-1)
else:
    print(min(cww_len))