#include <iostream>
using namespace std;
 
int main(){
	int n;
	cin>>n;
	if(n % 2 == 0){
		cout<<2<<endl;
	}
	
	if(n % 3 == 0){
		cout<<3<<endl;
	}
	
	if(n % 5 == 0){
		cout<<5<<endl;
	}
	
	if(n % 7 == 0){
		cout<<7<<endl;
	}
}

/**************************************************************
	Problem: 1299
	User: admin
	Language: C++
	Result: Accepted
	Time:12 ms
	Memory:2072 kb
****************************************************************/