#ifdef LOCAL111
#else
	#define NDEBUG
#endif
#include <bits/stdc++.h>

using namespace std;

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define RBP(i,a) for(auto& i : a)
#ifdef LOCAL111
	#define DEBUG(x) cout<<#x<<": "<<(x)<<endl
#else
	#define DEBUG(x) true
#endif
#define F first
#define S second
#define SNP string::npos
#define WRC(hoge) cout << "Case #" << (hoge)+1 << ": "
#define INF 1e8
template<typename T> void pite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}

typedef pair<int,int> P;
typedef long long int LL;
typedef unsigned long long ULL;
typedef pair<LL,LL> LP;

void ios_init(){
	//cout.setf(ios::fixed);
	//cout.precision(12);
#ifdef LOCAL111
	return;
#endif
	ios::sync_with_stdio(false); cin.tie(0);	
}

std::vector<bool> eratosthenes(int n){
	std::vector<bool> res(n+1,true);
	res[0] = false;
	res[1] = false;
	for(int i = 2; i*i <= n; i++){
		for(int j = 2; i*j <= n; j++){
			res[i*j] = false;
		}
	}
	return res;
}

int main()
{
	ios_init();
	LL L,H;
	cin >> L >> H;
	LL rt = sqrt(H);
	DEBUG(rt);
	auto res = eratosthenes(rt);
	int mapf = -1;
	RREP(i,SZ(res)){
		if(res[i]){
			mapf = i;
			break;
		}
	}
	if(H-L-5 > mapf){
		cout << L/mapf*mapf << endl;
	}else{
		int ans = -1;
		int pf = -1;
		REP(i,H-L+1){
			int minpf = -1;
			FOR(j,2,SZ(res)){
				if(res[j] and (i+L)%j == 0){
					minpf = j;
					break;
				}
			}
			if(pf <= minpf){
				pf = minpf;
				ans = i+L;
			}
		}
		cout << ans << endl;
	}
	return 0;
}