import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
		int k = scan.nextInt();
        int[] cardList = new int[n];
        for(int i = 0 ; i < n ; i++){
        	int cardNo = scan.nextInt()-1;
        	cardList[cardNo]++;
        }
        Arrays.sort(cardList);
        int count = 0;
		for(int i = n-1;i >= 0 ; i--){
			if(cardList[i] == 0){
				continue;
			}
			if(k <= 0){
            	break;
            }
            k -= cardList[i];
            count++;
		}

        System.out.println(count);
    }
}