def e(m,e,n):
    f = 1
    print("%d ^ %d mod %d" %(m,e,n))
    while e != 1:
        print("= %d ^ %d * %d mod %d" % (m,e,f,n))
        if e % 2 == 1:
            f *= m
            e -= 1
            f = f % n
        m = (m * m) % n
        e /= 2
    print("= %d * %d mod %d" % (m,f,n))
    c = (m*f) % n
    print("= %d" % c)

e(20,13,33)