#include<iostream>
#include<string>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
#include<vector>

using namespace std;

int main()
{
	int N;

	cin >> N;

	if (N == 2)
	{
		cout << 16;
		return 0;
	}

	if (N % 2 == 0)
		cout << 15;
	else if (N % 2 == 1)
	{
		if ((N / 2 + 1) % 2 == 0)
			cout << 15;
		else
			cout << 16;
	}

	return 0;
}