#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
  int n; cin >> n;
  //和＝(2a+n-1)n/2
  int ans = 0;
  if(n%2==0) ans = n / 2;
  else ans = n;
  cout << ans << endl;
  return 0;
}