import java.util.Scanner;
public class username
{
    public static void main(String args[])
    {
        Scanner cse = new Scanner(System.in);
        String s1 = cse.nextLine().trim();
        String s2 = cse.nextLine().trim();
        if(s1.matches("[a-zA-Z]+") && s2.matches("[a-zA-Z]+"))
        {
            System.out.println(s1+s2);
        }
        else
        {
            System.out.println("invalid input");
        }
        cse.close();
    }
}