#include <cstdio>
#include <algorithm>
#include <vector>
#include <queue>

using namespace std;

int main() {
	int n;
	scanf("%d", &n);
	int fler = 15;
	int step;
	int sum = 0;
	for (int i = n; i>=1; i--)
		if (sum - i >= 0) {
			sum-=i;
		} else {
			sum+=i;
		}
	printf ("%d\n", fler+sum);
	return 0;
}