#include <iostream>
using namespace std;
int main(){
  long long n;cin>>n;
  if(n <= 1)cout << 0 << endl;
  else{
    long long mx2 = 1;
    while(mx2 <= n)mx2*=2;
    mx2/=2;
    long long ans = 1;
    while(mx2){
      if(n & mx2){
        ans++;;
      }
      mx2 /= 2;
    }
    cout << n-(1LL<<(ans-1))+1 << endl;
  }
}