#include<bits/stdc++.h>
using namespace std;
int n,i,m,a[16] = {0,2,3,5,7,11,13,17,19,23,29,31,37,41,43,47};
int main(){
    cin >> n >> m;
    for(i = 1; i < 15; i++){
    	if(n == a[i]){
    		if(m == a[i + 1]){
    			cout<< "YES" << endl;
    			return 0;
    		}
    		cout<< "NO" << endl;
    	}
    }
    return 0;
}