import sys
import math

def main():
    n, m = map(int, sys.stdin.readline().split())
    if m >= n:
        print(1)
        return
    # Find all divisors of n
    divisors = set()
    for i in range(1, int(math.isqrt(n)) + 1):
        if n % i == 0:
            divisors.add(i)
            divisors.add(n // i)
    valid_d = []
    for d in divisors:
        if d >= 2 and d <= m:
            s = n // d
            if math.gcd(d, s) == 1:
                valid_d.append(d)
    if not valid_d:
        print(-1)
    else:
        max_d = max(valid_d)
        print(n // max_d)
    return

if __name__ == "__main__":
    main()