import java.util.*;
public class test {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        Deque<Integer> deque = new ArrayDeque<>();
        int n = in.nextInt();
        int m = in.nextInt();
        ArrayList<Integer> sizeArr = new ArrayList<>();

        for (int i = 0; i < n; i++) {
            int num = in.nextInt();
            deque.add(num);
        }
        //change to list so that it can be easily sublisted
        List<Integer> list = new ArrayList<Integer>(deque);

        //sub-queue loop
        for (int i = 0; i <= n-m; i++) {    //farthest index to start subqueue will be "n-m" (to n)
            HashSet<Integer> hs = new HashSet<>(list.subList(i, i+m));
            sizeArr.add(hs.size());
        }
        System.out.println(Collections.max(sizeArr));
    }
}