package main

import (
	"fmt"
	"math"
)

func getSieve(N int) []int {
	field := make([]bool, N + 1)
	sieve := make([]int, 0)
	for k := 2; k <= N; k++ {
		if field[k] {
			continue
		}
		for v := k * k; v <= N; v += k {
			field[v] = true
		}
		sieve = append(sieve, k)
	}
	return sieve
}

func getMinSieve(n int) int {
	for k := 2; k <= n; k++ {
		if n % k == 0 {
			return k
		}
	}
	return -1
}
func main() {
	var L int
	var H int
	fmt.Scanf("%d", &L)
	fmt.Scanf("%d", &H)
	sieve := getSieve(int(math.Sqrt(float64(H)) + 5))
	for l := len(sieve) - 1; l >= 0; l-- {
		p := sieve[l]
		if p * p > H {
			continue
		}
		for m := H / p; m * p >= L; m-- {

			if getMinSieve(m) >= p {
				fmt.Println(m * p)
				return
			}
		}
	}
}