#include <iostream>
using namespace std;

int main() {
	int n;
	cin>>n;
	if((n!=2)&&(n%2==0)){cout<<n<<endl;}else{
		n=n+3;
		if(n%2==0){cout<<n<<endl;}else{
			n=n+3;
			cout<<n<<endl;
		}
	}
	
	
	return 0;
}