#include <bits/stdc++.h>
using namespace std;
int main() {
	int64_t N;
	cin >> N;
	int64_t ans = 0;
	int64_t a = ((N / 2) + 1), b = ((N + 1) / 2 + 1);
	ans = (a * b - 1);
	cout << ans << endl;
	return 0;
}