import java.util.ArrayList;
import java.util.Deque;
import java.util.HashMap;
import java.util.Queue;
import java.util.Scanner;
import java.util.Stack;

public class Main {

    
    
    void fun1() {
        Scanner scan=new Scanner(System.in);
        String str=scan.next();
        int s=0;
        Stack<Character>st=new Stack<Character>();
        for(int i=0;i<str.length();i++) {
            Character ch=str.charAt(i);
            if(!st.empty()&&st.peek().equals(ch)) {
                st.pop();
                s++;
            }else {
                st.add(ch);
            }
        }
        System.out.println(s);
    }
    
    void fun2() {
        Scanner scan=new Scanner(System.in);
        long m;
        int n;
        
        m=scan.nextLong();
        n=scan.nextInt();
        long s=m;
        for(int i=0;i<n;i++) {
            long x=scan.nextInt();
            x=m-x;
            s=s-x;
        }
        
        if(s<=0) {
            s=0;
        }
        System.out.println(s);
    }
    
    void fun3() {
        Scanner scan=new Scanner(System.in);
        int n,k;
        int []arr=new int[20000];
        n=scan.nextInt();
        k=scan.nextInt();
        HashMap<Integer, Integer>map=new HashMap<Integer, Integer>();
        for(int i=0;i<n;i++) {
            int x=scan.nextInt();
            int y=scan.nextInt();
            x=x*2;
            y=y*2;
            for(int j=x;j<=y;j++)
                arr[j]+=1;
        }
        
        int t1=0,t2=0;
        ArrayList<Integer>arr1=new ArrayList<Integer>();
        ArrayList<Integer>arr2=new ArrayList<Integer>();
        for(int i=0;i<20000;i++)
        {
            if(arr[i]>=k) {
                //System.out.println(i);
                arr[i]=k;
                if(i==0||arr[i-1]!=k) {
                    t1=i;
                }
            }
            else if(i>0&&arr[i-1]==k) {
                t2=i-1;
                arr1.add(t1);
                arr2.add(t2);
            }
        }
        
        System.out.println(arr1.size());
        for(int i=0;i<arr1.size();i++) {
            System.out.println(arr1.get(i)/2+" "+arr2.get(i)/2);
        }
    }
    
    void fun4() {
        Scanner scan=new Scanner(System.in);
        int m=scan.nextInt();
        int n=scan.nextInt();
        ArrayList<Integer> arr=new ArrayList<Integer>();
        for(int i=0;i<m;i++) {
            int x=scan.nextInt();
            arr.add(x);
        }
        arr.sort(null);
        
        
        long s=0;
        long min=arr.get(m-1)*n;
        for(int i=0;i<=m-n;i++)cf
        {
            long max=arr.get(i+n-1);
            if(i==0) {
                for(int j=i;j<i+n;j++) {
                    s+=arr.get(j);
                }
            }else {
                s=s-arr.get(i-1)+arr.get(i+n-1);
                
            }
            //System.out.println("max="+max+"s="+s);
            long x=max*n-s;
            if(x<min) {
                min=x;
            }
        }
        
        System.out.println(min);
    }
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        

        Main demo=new Main();
        demo.fun4();
        
    }

}