#include<bits/stdc++.h>
using namespace std;
int n,i=2;
int main(){
	cin>>n;
	while(i*i<=n&&n%i!=0){ 
		i++;
	}
	if(i==n) cout<<"yes";
	if(i<n&&n%i==0) cout<<i;
	return 0;
}
/**************************************************************
	Problem: 1061
	User: zhangziang
	Language: C++
	Result: Wrong Answer
****************************************************************/