03. Substring

using System;
using System.Linq;
using System.Collections.Generic;

namespace Substring
{

    class Program
    {
        static void Main()
        {
            string sub = Console.ReadLine();
            string str = Console.ReadLine();

            while (str.Contains(sub))
            {
                str = str.Replace(sub, "");
            }

            Console.WriteLine(str);
        }
    }
}