#include <iostream>
using namespace std;

long long rec(long long num, long long dis){
    if(num > dis){
        return -1;
    }
    if(num == dis){
        return num;
    }
    
    int res1 = rec(num * 2, dis - num);
    int res2 = rec(num * 2 + 1, dis - num);
    
    if(res1 == -1 && res2 == -1){
        return -1;
    }
    if(res1 == -1){
        return res2;
    }
    if(res2 == -1){
        return res1;
    }
    if(res1 < res2){
        return res1;
    }else{
        return res2;
    }
    
}

int main(){
    long long d;
    cin >> d;
    cout << rec(1, d) << endl;
    return 0;
}