from random import getrandbits

BASE = 2**32

def tick():
    return getrandbits(32)

def _randint(n):
    # generate a random number in [0; n]
    ndigits = 1
    gen_range = BASE
    x = n
    while BASE <= x:
        x //= BASE
        ndigits += 1
        gen_range *= BASE
    gen_range -= 1 # BASE^ndigits - 1

    # Compute the "scale" with the properties:
    #  - gen_range/scale >= user_range
    #  - minimize (gen_range/scale - user_range)
    #  - scale >= 1
    if gen_range != n:
        scale = gen_range // (n + 1)
    else:
        scale = 1

    while True:
        k = 0
        for digit in xrange(ndigits):
            k *= BASE
            k += tick()
        k /= scale
        if k <= n:
            break
    return k

def randint(a, b):
    # generate a random number in [a; b]
    if b < a:
        raise ValueError("b < a")
    return a + _randint(b - a)