#include "bits/stdc++.h"

#define MOD 1000000007
#define rep(i, n) for(ll i=0; i < (n); i++)
#define rrep(i, n) for(ll i=(n)-1; i >=0; i--)
#define ALL(v) v.begin(),v.end()
#define rALL(v) v.rbegin(),v.rend()
#define FOR(i, j, k) for(ll i=j;i<k;i++)
#define debug_print(var) cerr << #var << "=" << var <<endl;
#define DUMP(i, v)for(ll i=0;i<v.size();i++)cerr<<v[i]<<" "
#define fi first
#define se second

using namespace std;
typedef long long int ll;
typedef vector<ll> llvec;
typedef vector<double> dvec;
typedef pair<ll, ll> P;
typedef long double ld;
struct edge{ll x, c;};

/**************************************
** A main function starts from here  **
***************************************/
int main(){
  ll N;
  cin >> N;
  for(ll i=N/2-1;;i++){
    ll ans = 0;
    ll x = i;
    while(x>0){
      ans += x;
      x/=2;
      if(ans>=N)break;
    }
    if(ans == N){
      cout << i<<endl;
      return 0;
    }
  }
  return 0;
}