#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,m=1;
    cin>>n;
    for(int i=2;i<=n-1;i++){
    	if(n%i==0){
    		m=0;
			cout<<i;
			break;
    	}
    }
    
    if(m==1){
    	cout<<"yes"<<endl;
    } 
    
	return 0;
}

/**************************************************************
	Problem: 1061
	User: LYY001
	Language: C++
	Result: Wrong Answer
****************************************************************/