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

typedef long long int64;
int64 prime_factor(int64 n)
{
  for(int64 i = 2; i * i <= n; i++) if(n % i == 0) return(i);
  return(-1);
}

vector< bool > get_prime(int n){
  vector< bool > prime( n + 1, true);
  
  if(n >= 0) prime[0] = false;
  if(n >= 1) prime[1] = false;
  
  for(int i = 2; i * i <= n; i++){
    if(prime[i]){
      for(int j = i + i; j <= n; j += i) prime[j] = false;
    }
  }
  
  return prime;
}

int main()
{
  vector< bool > prime = get_prime(100000);
  int64 L, H;
  cin >> L >> H;
  for(int64 i = 100000; i >= 2; i--) {
    if(prime[i] && L <= i * i && i * i <= H) {
      cout << i * i << endl;
      exit(0);
    }
  }
  pair< int64, int64 > ret(2, 2);
  for(int64 i = L; i <= H; i++) {
    ret = max(ret, {prime_factor(i), i});
  }
  cout << ret.second << endl;
}