#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef struct {
	ll x,y;
} _pos;
int main () {
	int n,K;cin >> n >> K;
	_pos pos[n];for (int i = 0;i < n;i++) {
		cin >> pos[i].x >> pos[i].y;
	}
	ll ans = 9223372036854775000;
	for (int i = 0;i < n;i++) {
		for (int j = 0;j < n;j++) {
			for (int k = 0;k < n;k++) {
				for (int l = 0;l < n;l++) {
					ll x[]={pos[i].x,pos[j].x,pos[k].x,pos[l].x};
					ll y[]={pos[i].y,pos[j].y,pos[k].y,pos[l].y};
					sort(x,x+4);
					sort(y,y+4);
					int cnt=0;
					for (int m = 0;m < n;m++) {
						if (x[0]<=pos[m].x&&pos[m].x<=x[3]&&y[0]<=pos[m].y&&pos[m].y<=y[3]) {
							cnt++;
						}
					}
					if (cnt>=K) ans = min(ans,(x[3]-x[0])*(y[3]-y[0]));
				}
			}
		}
	}
	cout << ans << endl;
}