#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;

const int N=100000+10;
typedef unsigned long long ll;

ll tot=0,lefT=0,righT=0,l=0,r=0;
int poS[N];

inline void righT_push(){
	righT+=(ll)(r-l+1)*(ll)(poS[r+1]-poS[r]);
	tot+=righT;
	lefT+=(ll)poS[++r]-poS[l];
}

inline void lefT_pop(){
	tot-=lefT;
	lefT-=(ll)(r-l)*(ll)(poS[l+1]-poS[l]);
	righT-=(ll)poS[r]-poS[l++];
}

int main()
{
	freopen("qwa.in","r",stdin);
	freopen("qwa.out","w",stdout);
	int n,k;
	scanf("%d%d",&n,&k);
	for(int i=0;i<n;i++)scanf("%d",&poS[i]);
	sort(poS,poS+n);
	//for(int i=0;i<n;i++)printf("%d ",poS[i]);puts("A");
	for(int i=1;i<k;i++)righT_push();
	ll out=tot;
	for(int i=k;i<n;i++){
		lefT_pop();
		righT_push();
		//cout<<tot<<' '<<lefT<<' '<<righT<<' '<<endl;
		if(tot<out)out=tot;
	}
	cout<<out;//printf("%d",out);
	return 0;
}