#include <cstdio>
#include <cstring>
#include <algorithm>
#include <queue>
#include <cmath>
 
using namespace std;
typedef long long LL;
 
struct node{
	LL x , y;
}a[100];
 
int main()
{
	int n , m;
	scanf("%d %d",&n , &m);
	for(int i = 1 ; i <= n ; i++) scanf("%lld %lld",&a[i].x , &a[i].y);
	LL ans = 1LL << 62;
	for(int i = 1 ; i <= n ; i++){
		for(int j = i + 1 ; j <= n ; j++){
			for(int k = 1 ; k <= n ; k++){
				for(int l = k + 1 ; l <= n ; l++){
					int sum = 0;
					LL lx = min(a[i].x , a[j].x) , hy = max(a[i].y , a[j].y);
					LL ly = min(a[k].y , a[l].y) , hx = max(a[k].x , a[l].x);
					for(int h = 1 ; h <= n ; h++){
						if(a[h].x >= lx && a[h].x <= hx && a[h].y >= ly && a[h].y <= hy)
							sum++;
					}
					if(sum >= m) ans = min(ans , (hx - lx) * (hy - ly));
				}
			}
		}
	}
	printf("%lld\n",ans);
}