#include <algorithm>
#include <cassert>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <deque>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>

#define FOR(i,k,n) for (int (i)=(k); (i)<(n); ++(i))
#define rep(i,n) FOR(i,0,n)
#define pb push_back
#define eb emplace_back
#define all(v) begin(v), end(v)
#define debug(x) cerr<< #x <<": "<<x<<endl
#define debug2(x,y) cerr<< #x <<": "<< x <<", "<< #y <<": "<< y <<endl

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<i_i, int> p_i;
typedef vector<int> vi;
typedef vector<vector<int> > vvi;
typedef vector<ll> vll;
typedef vector<vector<ll> > vvll;
typedef vector<char> vc;
typedef vector<vector<char> > vvc;
typedef vector<double> vd;
typedef vector<vector<double> > vvd;
template<class T> using vv=vector<vector< T > >;
typedef deque<int> di;
typedef deque<deque<int> > ddi;

// cout vector
template<typename T> ostream& operator<<(ostream& s, const vector<T>& v) {
    int len = v.size();
    for (int i = 0; i < len; ++i) {
        s << v[i]; if (i < len - 1) s << "\t";
    }
    return s;
}

// cout 2-dimentional vector
template<typename T> ostream& operator<<(ostream& s, const vector< vector<T> >& vv) {
    int len = vv.size();
    for (int i = 0; i < len; ++i) {
        s << vv[i] << endl;
    }
    return s;
}

int MAX_PRIME; // in this problem up to 10^6
deque<bool> isprime;
vector<int> primes;
void init_prime(int mp) {
    MAX_PRIME = mp;
    isprime.resize(MAX_PRIME+1, true);
    isprime[0] = isprime[1] = false;
    primes.clear();
    for(int i = 2; i <= MAX_PRIME; i++) {
        if (isprime[i]) {
            primes.push_back(i);
            for(int j = i*2; j <= MAX_PRIME; j += i) {
                isprime[j] = false;
            }
        }
    }
}

ll min_factor(ll n) {
    rep (i, upper_bound(all(primes), (int)sqrt(n)) - begin(primes)) {
        if ( n % primes[i] == 0 ) {
            return primes[i];
        }
    }
    return (ll)INT_MAX;
}

int main() {
    ll l, h;
    cin >> l >> h;
    init_prime(1000000);
    int maxminfact = 2;
    ll maxminproduct = h - (h % 2 == 1 ? 1 : 0);
    for (int i = upper_bound(all(primes), (int)sqrt(h)) - begin(primes) - 1; i >= 0; --i) {
        if ( primes[i] < maxminfact ) {
            break;
        }
        for (ll j = h / primes[i]; j * primes[i] >= l; --j) {
            int tmp_fact = min(primes[i], (int)min_factor(j));
            if ( tmp_fact > maxminfact ) {
                maxminfact = tmp_fact;
                maxminproduct = j * primes[i];
            }
        }
    }
    printf("%lld\n", maxminproduct);

    return 0;
}