1. 

import java.io.*;
import java.util.*;

class Main {

public static void main(String...args) throws Exception
{
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String input;
String s[];
long t;

while( (input = reader.readLine()) != null)
{
s = input.split(" ");
t = 2*Long.parseLong(s[0])*Long.parseLong(s[1]);
System.out.println(t);
}
}
}