import java.util.HashMap;
import java.util.Scanner;
public class Student20191023 {
static int minerror = 0;
static int check = 0;
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String in = scan.nextLine();
String [] inputarr = in.split(" ");
int i, j;
int input = Integer.parseInt(inputarr[0]);
int bucket = Integer.parseInt(inputarr[1]);
int[] numbers = new int[input];
for(i = 2, j = 0; i < inputarr.length; i++, j++) {
numbers[j] = Integer.parseInt(inputarr[i]);
}
int[] items = new int[input - 1];
for(i = 0; i < input - 1; i++){
items[i] = i + 1;
}
insertionSort(numbers, numbers.length);
int[] bucketarr = new int[bucket - 1];
solution(numbers, items, bucketarr, bucket - 1);
System.out.println(minerror);
scan.close();
}
public static void insertionSort(int[] A, int n) {
int i;
for(i = 1; i < n; i++) {
int j = 0;
int m, k;
for(j = 0; j < i; j++)
if(A[j] > A[i])
break;
m = (int) A[i];
for(k = i; k > j; k--)
A[k] = A[k-1];
A[j] = m;
}
}
public static void solution(int[] arr, int[] items, int[] bucket, int k){
if(k == 0){
int ret = divide(bucket, arr);
if(check == 0){
check++;
minerror = ret;
}
else if(check != 0){
if(minerror > ret){
minerror = ret;
}
}
return;
}
int lastIndex = bucket.length - k - 1;
for(int i = 0; i < items.length; i++){
if(bucket.length == k){
bucket[0] = items[i];
solution(arr, items, bucket, k-1);
}
else if(bucket[lastIndex] < items[i]){
bucket[lastIndex + 1] = items[i];
solution(arr, items, bucket, k - 1);
}
}
}