very easy?

#include <bits/stdc++.h>
using namespace std;
int a,f=0;
int main(){
	cin>>a;
	if(a==1)
	{
		cout<<"No";
		return 0;
	}
	
	for(int i=2;i<a;i=i+1)
	{
		if(a%i==0)
		{
			f=1;
			
		}
		
	}
    if(f==1)
    {
    	cout<<"No"<<endl;
    	
	}
	else
	{
		cout<<"Yes"<<endl;
	}
	
	
	return 0;
	
}