def main():
    S = list(input())
    cww_lengthes = []
    cww_store = []
    for i in range(len(S) - 1):
        if S[i] == 'c':
            cww_store.append(i)
            for j in range(i + 1, len(S)):
                if S[j] == 'w':
                    if len(cww_store) == 2:
                        cww_lengthes.append(j - cww_store[0] + 1)
                        cww_store = []
                    if len(cww_store) == 1:
                        cww_store.append(i)
    print(min(cww_lengthes) if cww_lengthes else -1)


if __name__ == '__main__':
    main()