import std.stdio, std.conv, std.string;
import std.algorithm, std.array, std.container, std.typecons;
import std.numeric, std.math;
import core.bitop;

T RD(T = string)() { static string[] ss; while(!ss.length) ss = readln.chomp.split; string res = ss[0]; ss.popFront; return res.to!T; }
string RDR()() { return readln.chomp; }
T[] ARR(T)(in string str) { return str.split.to!(T[]); }
size_t[] MAKE_IDX(alias less = "a < b", Range)(Range range) { auto idx = new size_t[](range.length); makeIndex!(less)(range, idx); return idx;}
size_t MIN_POS(alias less = "a < b", Range)(Range range) { auto r = minPos!(less)(range); return range.length - r.length; }

bool INSIDE(T)(T x, T b, T e) { return x >= b && x < e; }

long mod = pow(10, 9) + 7;
void moda(ref long x, long y) { x = (x + y) % mod; }
void mods(ref long x, long y) { x = ((x + mod) - (y % mod)) % mod; }
void modm(ref long x, long y) { x = (x * y) % mod; }

struct UnionFind
{
	void init(long n) { par = new long[](n); foreach (i; 0..n) par[i] = i; }
	long root(long i) { return par[i] == i ? i : (par[i] = root(par[i])); }
	bool same(long i, long j) { return root(i) == root(j); }
	void unite(long i, long j) { i = root(i); j = root(j); if (i == j) return; par[i] = j; }
	long[] par;
}

void main()
{
	auto N = RD!long;
	auto K = RD!long;
	long[] x, y;
	foreach (i; 0..N)
	{
		x ~= RD!long;
		y ~= RD!long;
	}
	long[] ans;
	foreach (i; 0..N)
	{
		foreach (j; i+1..N)
		{
			foreach (k; j+1..N)
			{
				auto xb = min(min(x[i], x[j]), x[k]);
				auto xe = max(max(x[i], x[j]), x[k]);
				auto yb = min(min(y[i], y[j]), y[k]);
				auto ye = max(max(y[i], y[j]), y[k]);
				long cnt;
				foreach (l; 0..N)
				{
					if (INSIDE(x[l], xb, xe+1) && INSIDE(y[l], yb, ye+1))
						++cnt;
				}
				if (cnt >= K) ans ~= (xe - xb) * (ye - yb);
			}
		}
	}
	ans.sort();
	
	writeln(ans[0]);
	stdout.flush();
}