class Program
{
    static void Main(string[] args)
    {
        string inputAll = Console.ReadLine()!;
        string inputGroup = Console.ReadLine()!;

        int all = int.Parse(inputAll);
        int group = int.Parse(inputGroup);
        List<int> numList = new List<int>();

        for (int i = 0; i < all; i++)
        {
            string inputNum = Console.ReadLine()!;
            numList.Add(int.Parse(inputNum));
        }
        numList.Sort();

        Console.WriteLine(numList[numList.Count - 1] - numList[0]);
    }
}