#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>

#define REP(i,s,n) for(int i=(int)(s);i<(int)(n);i++)

using namespace std;
typedef long long int ll;
typedef vector<int> VI;
typedef pair<int, int> PI;
const double EPS=1e-9;

const int N = 105000;
int a[N];

int b[2 * N];

int main(void){
  ll l, h;
  cin >> l >> h;
  REP(i, 2, N) a[i] = 1;
  REP(i, 2, N) {
    REP(j, 2, N / i) {
      a[i * j] = 0;
    }
  }
  // a: prime
  if (h - l < 2 * N) {
    REP(i, 2, N) {
      if (a[i]) {
	for (ll j = max((l + i - 1) / i * i, 2LL * i); j <= h; j += i) {
	  if (b[j - l] == 0) b[j - l] = i;
	}
      }
    }
    int ma = 0;
    REP(i, 0, h - l + 1) {
      if (b[i] >= b[ma]) ma = i;
    }
    cout << ma + l << endl;
    return 0;
  }
  assert(0);
}