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

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