#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <cmath>
#include <map>
#include <queue>
#include <iomanip>
#include <set>
#include <tuple>
#define mkp make_pair
#define mkt make_tuple
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define all(v) v.begin(),v.end()
using namespace std;
typedef long long ll;
const ll MOD=1e9+7;
template<class T> void chmin(T &a,const T &b){if(a>b) a=b;}
template<class T> void chmax(T &a,const T &b){if(a<b) a=b;}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  ll N;
  cin>>N;

  vector<ll> num(61,0);
  num[0]=1;
  for(int k=0;k<60;k++){
    num[k+1]=num[k];
    if((1ll<<k)&N) num[k+1]*=2;
  }

  ll ans=N;
  ll cnt=1;
  ll all=num[60];
  for(int k=60;k>=0;k--){
    if(N&(1ll<<k)){
      if(cnt+num[k]<=all/2){
        cnt+=num[k];
        ans^=(1ll<<k);
      }
    }
  }

  cout<<ans<<endl;

  return 0;
}