def main():
    S = input()
    C = S.find('c', 0, )
    cww = S.find('cww')
    if cww == -1:
        if C >= 0:
            W1 = S.find('w', C + 1)
            if W1 > C:
                W2 = S.find('w', W1 + 1,)
                if W2 < 0:
                    print(-1)
                    return
                elif C >= 0 and W1 - C > 0:
                    print(W2 - C + 1)

    else:
        print(-1)


if __name__ == '__main__':
    main()