#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector< int > vi;
typedef vector< vi > vvi;
typedef vector< ll > vl;
typedef vector< vl > vvl;

ll L, H;

void init(){
	cin >> L >> H;
}

vi np;
vi pt;

void preprocess(){
	np = vi( ( int ) 1e5 + 1 );
	for( int i = 2; i < np.size(); ++i )
		if( not np[ i ] ){
			pt.push_back( i );
			for( int j = i + i; j < np.size(); j += i )
				np[ j ] = 1;
		}
}

void solve(){
	for( int i = pt.size() - 1; i >= 0; --i ){
		int p = pt[ i ];
		for( ll j = H / p * p; j >= max( 1LL * p * p, L ); j -= p ){
			if( p == j ) continue;
			int ng = 0;
			for( int k = 0; k < i; ++k )
				if( j % pt[ k ] == 0 ){
					ng = 1;
					break;
				}
			if( not ng )
				cout << j << endl, exit( 0 );
		}
	}
}

signed main(){
	ios::sync_with_stdio( 0 );
	init();
	preprocess();
	solve();
	return 0;
}