#include <iostream>
using namespace std;
long long n, start, i, rasp1, rasp;
int main()
{
	cin>>n;
	start=15;
	start=start+((n*(n+1))/2LL);
	for(i=n; i>=1; i--)
	{
		if(start-2*i>=15)
			start=start-2*i;
	}
	rasp1=start;
	if(((n*(n+1))/2LL)%2==0)
		rasp=15;
	else rasp=16;
	cout<<rasp1;
}