#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n);i++)
#define sz(x) int(x.size())
typedef long long ll;
typedef long double ld;
typedef pair<int,int> P;
typedef pair<ll, int> PL;
constexpr int INF = 2e9;

int main() {
  int n;
  cin >> n;
  int res = 0;
  for (int a = 0; a <= n; a++) {
    for (int b = 0; a + b <= n; b++) {
      res++;
    }
  }
  cout << res << endl;
  return 0;
}