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

typedef long long ll;

signed main(){
  ll N; cin >> N;
  ll maxv = 0;
  ll orgv = 0;
  
  while( N ){
    orgv += N / 2;
    maxv = max( maxv, orgv + N / 2 );
  }

  cout << maxv - orgv << endl;
  return 0;
}