#include <stdio.h>
#include <stdlib.h>
#include <math.h>

long func(long a){
  if(a%2 == 0) return 2;
  else{
    long i ;
    for(i=3;i<= sqrt(a);i+=2){
      if(a%i==0) return i;
    }
  }
  return a;
}

int main(){
  long a,b,i,j,buff;
  long result , result_prime;
  long prime;
  
  scanf("%ld %ld",&a,&b);
  result_prime = func(a);

  for(i= result_prime; i<=sqrt(b);i+=2){
    prime = func(i);
    if(prime>=result_prime){
      ((a/i)>i)?(j=(a/i)):(j=i);
      for(j=buff;j<=b/i;j++){
	if((i*j>=a)&&(i*j<=b)){
	  result_prime = prime;
	  result = i*j;
	}
      }
    }
  }
  printf("%ld\n",result);
  return 0;
}