substring

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

namespace mid_exam
{
    class Program
    {
        static void Main(string[] args)
        {

            string wordToFind = Console.ReadLine().ToLower();
            string sentence = Console.ReadLine();


            while (sentence.Contains(wordToFind))
            {
                int index = sentence.IndexOf(wordToFind);
                sentence = sentence.Remove(index, wordToFind.Length);
            }

            Console.WriteLine(sentence);
        }
    }
}