#include<bits/stdc++.h>
// #include<atcoder/all>

using namespace std;
// using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using P = pair<int,int>;
#define rep(i,n) for(ll i = 0;i < (ll)n;i++)
#define ALL(x) (x).begin(),(x).end()
#define MOD 1000000007



int main(){
  
  ll n;
  cin >> n;
  int b = 0;
  rep(i,60)if(n >> i & 1)b++;
  ll k = (1ll << (b-1));
  ll res = 0;
  rep(i,60)if(n >> i & 1){
    if(k & 1)res += (1ll << i);
    k >>= 1;
  }
  cout << res << "\n";
  

  return 0;
}