#include <bits/stdc++.h>

using namespace std;

#define ll long long
#define INF (1LL<<62)

ll x[50],y[50];
int N,K;

int check(ll lx,ll ly,ll rx,ll ry){
	int ans = 0;
	for(int i = 0;i < N;i++){
		ll nx = x[i];
		ll ny = y[i];
		if(!(lx <= nx && nx <= rx))continue;
		if(!(ly <= ny && ny <= ry))continue;
		ans++;
	}
	return ans;
}

ll saiki(int num,int at,ll lx,ll ly,ll rx,ll ry){

	ll ret = (rx-lx)*(ry-ly);
	if(check(lx,ly,rx,ry)!=K)ret = INF;
	if(num == 4)return ret;

	for(int i = at;i<N;i++){
		ll nx = x[i];
		ll ny = y[i];
		ll v = saiki(num+1,i+1,min(lx,nx),min(ly,ny),max(rx,nx),max(ry,ny));
		ret = min(ret,v);
	}
	return ret;
}

int main(){
	cin>>N>>K;
	for(int i = 0;i < N;i++){
		cin >> x[i] >> y[i];
	}

	cout << saiki(0,0,INF,INF,-INF,-INF) << endl;
}