#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
using namespace std;
typedef long long int ll;
typedef pair<ll, int> P;

const ll MAX=110001;
 
vector<ll> prime;
bool isprime[MAX];
 
void sieve(){
	for(ll i=3; i<MAX; i+=2){
		isprime[i]=1;
	}
	isprime[2]=1;
	prime.push_back(2);
	for(ll i=3; i<MAX; i++){
		if(isprime[i]){
			prime.push_back(i);
			for(ll j=2*i; j<MAX; j+=i){
				isprime[j]=0;
			}
		}
	}
	return;
}

int main()
{
	ll l, h;
	cin>>l>>h;
	sieve();
	int i1=0, i2=prime.size()-1;
	while(i1!=i2){
		int i0=(i1+i2+1)/2;
		if(prime[i0]*prime[i0]<=h){
			i1=i0;
		}else{
			i2=i0-1;
		}
	}
	if(l<=prime[i1]*prime[i1]){
		cout<<(*(upper_bound(prime.begin(), prime.end(), h/prime[i1])-1))*prime[i1]<<endl;
		return 0;
	}
	vector<P> fac[5000000];
	ll x[5000000];
	for(ll i=l; i<=h; i++) x[i-l]=i;
	for(auto p:prime){
		ll x0=(l+p-1)/p*p;
		for(ll x1=x0; x1<=h; x1+=p){
			int e=0;
			while(x[x1-l]%p==0){
				x[x1-l]/=p;
				e++;
			}
			fac[x1-l].push_back(P(p, e));
		}
	}
	for(ll i=l; i<=h; i++){
		if(x[i-l]>1) fac[i-l].push_back(P(x[i-l], 1));
	}
	ll mx=0, ans;
	for(ll i=h; i>=l; i--){
		if(fac[i-l].size()==1 && fac[i-l][0].second==1) continue;
		if(fac[i-l][0].first>mx){
			mx=fac[i-l][0].first;
			ans=i;
		}
	}
	cout<<ans<<endl;
	return 0;
}