def main():
    import sys
    input = sys.stdin.read().split()
    X = int(input[0])
    Y = int(input[1])
    
    if Y == 0:
        print(0)
        return
    
    # Build min_prime_factor array up to Y
    max_Y = Y
    mpf = list(range(max_Y + 1))
    for i in range(2, int(max_Y**0.5) + 1):
        if mpf[i] == i:  # i is a prime
            for j in range(i * i, max_Y + 1, i):
                if mpf[j] == j:
                    mpf[j] = i
    
    max_f = 0
    for r in range(X, Y + 1):
        current = r
        valid = True
        product = 1
        tmp = current
        while tmp > 1:
            p = mpf[tmp]
            count = 0
            while tmp % p == 0:
                count += 1
                tmp //= p
            if p % 4 == 3:
                if count % 2 != 0:
                    valid = False
                    break
            else:
                if p % 4 == 1:
                    product *= (count + 1)
        if valid:
            current_f = 4 * product
            if current_f > max_f:
                max_f = current_f
    print(max_f)

if __name__ == "__main__":
    main()