#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;
	if (n%2== 0 && (n/2)%2 ==0) {
		printf ("15\n");
		return 0;
	} else if (n%2==0){
		printf ("16\n");
		return 0;
	}
	if (n%2 == 1 && (n/2) % 2 == 1) {
		printf ("15\n");
	} else {
		printf ("16\n");
	}
	return 0;
}