#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  n <<= 24;
  int *arr = new int[n], x = 0;
  for (int i = 0; i < n / 2 + (n % 2 != 0); i++) {
    if (arr[i]) {
      x++;
    }
  }
  cout << x << '\n';
}
