import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.StringTokenizer;

public class temp {
	// static int N;

	public static void main(String[] args) throws Exception {
		BufferedReader r = new BufferedReader(new FileReader("file.in"));
		PrintWriter w = new PrintWriter(new BufferedWriter(new FileWriter("file.out")));
		//BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		//PrintWriter w = new PrintWriter(System.out);
		for (String line = r.readLine(); line != null; line = r.readLine()) {
		       w.println(2*Integer.parseInt(line));
		    }
		w.close();
	}
	public static void parse(BufferedReader r) throws Exception {
		/*
		StringTokenizer st = new StringTokenizer(r.readLine());
		X= Integer.parseInt(st.nextToken());
		Y= Integer.parseInt(st.nextToken());
		M= Integer.parseInt(st.nextToken());
		*/
	}
	public static void parseN (BufferedReader r) throws Exception {


	}
}