C++ :

#include<iostream>
using namespace std;

long long f(long long n)
{
     if(n==1)return 1;
     else 
     {
          long long k = f((n+1)/2);
          if(n%2)
          {
                if(k==1)return n;
                else return (k-1)*2; 
          }
          else return 2*k;
     }  
          
 }

int main()
{
    long long n;
    while(cin>>n)
    cout<<f(n)<<endl;
    return 0;
    
}

Java :

import java.io.BufferedInputStream;
import java.util.Scanner;


public class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
        Scanner cin=new Scanner(new BufferedInputStream(System.in));
       la: while(cin.hasNext()){
        int N=cin.nextInt();
        if(N==1){System.out.println(1); continue la;}
       N-=1;
        int base=0;
        while(true)
        {
        
        	if(N-Math.pow(2, base)<=0)
        	{
        		
        		System.out.println(N*2);
        		break;
        	}
        	else
        	{
        		N-=Math.pow(2, base);
        	
        		base++;
        	}
        }
      //  System.out.println(N2);
	}
	}

}