def main():
    text = input()

    cww_length = []
    cww_store = []
    for i in range(len(text)):
        if text[i] == 'c':
            cww_store.append(i)
            for j in range(i, len(text)):
                if text[j] == 'w':
                    w1 = j
                    for k in range(j + 1, len(text)):
                        if text[k] == 'w':
                            cww_store.append(k)
                            if len(cww_store) == 2:
                                cww_length.append(k - i + 1)
                                cww_store = []
    print(min(cww_length) if cww_length else -1)
                                                     

if __name__ == '__main__':
    main()