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

#define LL long long 

const int maxn=100000+10;
const LL INF=999999999999999ll;

LL a[maxn], ans=INF, n, k;

LL Qin() {
	LL x=0;
	char c=getchar();
	while(c<'0' || c>'9') c=getchar();
	while(c>='0' && c<='9') x=x*10+c-'0', c=getchar();
	return x;
}

void init() {
	n=Qin(); k=Qin();
	for(int i=1; i<=n; i++) a[i]=Qin();
	sort(a+1, a+1+n);
	for(int i=1; (i+k-1)<=n; i++) {
		int t=i+k-1;
		LL cnt=0, cc=1;
		for(int j=t; j>=i; j--) {
			cnt+= (LL) (k+1-2*cc)*a[j];
			cc++;
		}
		ans=min(ans, cnt);
	}
	printf("%lld\n", ans);
}

int main() {
	freopen("qwa.in", "r", stdin);
	freopen("qwa.out", "w", stdout);
	init();
	return 0;
}