#include <bits/stdc++.h>
using namespace std;
 
using ll = long long; using ld = long double; using ull = unsigned long long; using uint = unsigned int;
using vi  = vector<int>; using vb  = vector<bool>; using vd  = vector<double>; using vl  = vector<ll>;
using vvi = vector<vi>;  using vvb = vector<vb>;   using vvd = vector<vd>;     using vvl = vector<vl>;
 
#define REP(i,n) for(ll i=0; i<(n); ++i)
#define FOR(i,b,n) for(ll i=(b); i<(n); ++i)
 
ll min_prime(ll n) {
	FOR(i, 2, sqrt(n)+1) if (n%i == 0) return i;
	return 1;
}

int main() {
	cin.tie(0);
	ios_base::sync_with_stdio(false);
	cout << fixed << setprecision(30);
	ll n, m; cin >> n >> m;

	if ((ll)sqrt(m) * (ll)sqrt(m) >= n) {
		ll x = sqrt(m);
		for (ll i = m; i >= n; --i) if(i%x==0){
			cout << i << endl;
			return 0;
		}
	}

	ll ma = 1;
	ll mai = 1;
	for (ll i = m; i >= n; --i) {
		ll x = min_prime(i);
		if (ma < x) {
			ma = x;
			mai = i;
		}
	}

	cout << mai << endl;
	return 0;
}