#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

#define REP(i,s,e) for (i = s; i <= e; i++)
#define rep(i,n) REP (i,0,(int)(n)-1)
#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP (i,(int)(n)-1,0)
#define INF (int)1e8
#define MOD (int)(1e9+7)

typedef long long ll;

bool prime[100001];

ll least_prime(ll x) {
    for (int i = 2; i * i <= x; i++) if (x % i == 0)
        return i;
    return x;
}

int main(void) {
    for (int i = 2; i <= 100000; i++)
        prime[i] = true;
    for (int i = 2; i * i <= 100000; i++) if (prime[i]) {
        for (int j = i*2; j <= 100000; j+=i)
            prime[j] = false;
    }

    ll l, h;
    cin >> l >> h;
    for (int x = sqrt(h); ; x--) {
        if (prime[x]) for (ll y = h / x; y * x >= l; y--) {
            if (least_prime(y) >= x) {
                cout << y * x << endl;
                return 0;
            }
        }
    }
    return 0;
}