#include <iostream>
using namespace std;
int n, sol = 100000000;

void Back(int pas, int now)
{
    if(pas == n + 1)
    {
        if(now >= 0)
            sol = min(sol, now);
        return;
    }
    Back(pas + 1, now + pas);
    Back(pas + 1, now - pas);
}

int main()
{
    cin >> n;
    if(n % 4 == 0 || n % 4 == 3)
        cout << "15\n";
    else
        cout << "16\n";
    return 0;
}