using System.Numerics;

public class Program
{
    public static void Main()
    {

        //BigInteger num = BigInteger.Parse(Console.ReadLine() ?? string.Empty);
        //int num = int.Parse(Console.ReadLine() ?? string.Empty);
        string[] moji = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        string[] moji2 = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string str = Console.ReadLine() ?? string.Empty;

        int card =int.Parse(moji[0]);
        int get = int.Parse(moji[1]);
        int[] ints = new int[card];

        for(int i =0; i < card; i++)
        {
            ints[int.Parse(moji2[i])-1]++;
        }
        Array.Sort(ints);

        int count = 0;
        for(int i = ints.Length-1;i >= 0;i--)
        {
            count++;
            get-=ints[i];
            if(get <= 0)
            {
                break;
            }
        }
        Console.WriteLine(count);
    }
}