---

using System;

class Program
{
    static void Main()
    {
        Console.Write("N1 = ");
        int n1 = int.Parse(Console.ReadLine());
        Console.Write("N2 = ");
        int n2 = int.Parse(Console.ReadLine());
        Console.Write("S1 = ");
        string s1 = Console.ReadLine();
        Console.Write("S2 = ");
        string s2 = Console.ReadLine();

        n1 = Math.Min(n1, s1.Length);
        n2 = Math.Min(n2, s2.Length);

        string s3 = s1.Substring(0, n1) + s2.Substring(s2.Length - n2);

        Console.WriteLine("S3 = " + s3);
    }
}