import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        char temp = 'a';

        int n = sc.nextInt();  int k = sc.nextInt();
        sc.nextLine();
        String s = sc.nextLine();

        while (k > 0) {
            if (s.contains(String.valueOf(temp))) {
                s = s.replaceFirst(String.valueOf(temp),"");
                k--;
            } else
                temp++;
        }

        System.out.println(s);
    }
}