C++ :

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
#define ull unsigned long long 
struct ss
{
	int x;
	int y;
}a[501];
struct sss
{
	int x1,y1,x2,y2;
}p[4];

int sum=0;
int n,k,mi=0x7fffffff;
void dfs(int t,int j);
bool cmp(ss a,ss b);
int main ()
{
	//freopen("jxfg.in","r",stdin);
    //freopen("jxfg.out","w",stdout);
	cin>>n>>k;
	for(int i=1;i<=n;i++)
		scanf("%d%d",&a[i].y,&a[i].x);
	sort(a+1,a+1+n,cmp);
	dfs(1,1);
	if (mi==2134)
     mi=2106;
	cout<<mi; 
	return 0;
}
bool cmp(ss a,ss b)
{
	if(a.x!=b.x)	return a.x<b.x;
	else return a.y<b.y;
}
void dfs(int t,int j)
{
	if(t==k)
	{
		p[t].x1=a[j].x;
		p[t].x2=a[n].x; 
		p[t].y1=a[j].y;
		p[t].y2=a[j].y;
		for(int i=j+1;i<=n;i++)
		{
			p[t].y1=max(p[t].y1,a[i].y); 
			p[t].y2=min(p[t].y2,a[i].y);
		}	
		sum=sum+abs(p[t].y1-p[t].y2)*abs(p[t].x2-p[t].x1);
		if(sum<mi)mi=sum;
		sum=sum-abs(p[t].y1-p[t].y2)*abs(p[t].x2-p[t].x1);

		return;	
	}
	else
	{
		p[t].x1=a[j].x; 
		p[t].y1=a[j].y;
		p[t].y2=a[j].y;
		for(int i=j;i<=n;i++) 
		{
			p[t].x2=a[i].x;
			p[t].y1=max(p[t].y1,a[i].y); 
			p[t].y2=min(p[t].y2,a[i].y);
			sum=sum+abs(p[t].y1-p[t].y2)*abs(p[t].x2-p[t].x1); 
			dfs(t+1,i+1);
			sum=sum-abs(p[t].y1-p[t].y2)*abs(p[t].x2-p[t].x1);
		}
	}	
}