#include <bits/stdc++.h>
#define rep(i, n) for (ll i = 0; i < (ll)(n); ++i)
#define rep2(i, s, n) for (ll i = s; i < (ll)(n); i++)
#define repr(i, n) for (ll i = n; i >= 0; i--)
#define pb push_back
#define COUT(x) cout << (x) << "\n"
#define COUTF(x) cout << setprecision(15) << (x) << "\n"
#define ENDL cout << "\n"
#define DF(x) x.erase(x.begin())
#define ALL(x) x.begin(), x.end()
#define SORT(x) sort(ALL(x))
#define RSORT(x) sort(x.rbegin(), x.rend())
#define REVERSE(x) reverse(ALL(x))
#define MAX(x) *max_element(ALL(x))
#define MAXI(x) max_element(ALL(x)) - x.begin()
#define SUM(x) accumulate(ALL(x), 0)
#define COUNT(x, y) count(ALL(x), y);
#define ANS cout << ans << "\n"
#define YES cout << "YES\n";
#define NO cout << "NO\n";
#define Yes cout << "Yes\n";
#define No cout << "No\n";
#define YN YES else NO
#define yn Yes else No
#define init() \
  cin.tie(0);  \
  ios::sync_with_stdio(false)
#define LINE cerr << "[debug] line: " << __LINE__ << "\n";
#define debug(x) cerr << "[debug] " << #x << ": " << x << "\n";
#define debugV(v)                       \
  cerr << "[debugV] " << #v << ":";     \
  rep(z, v.size()) cerr << " " << v[z]; \
  cerr << "\n";
using namespace std;
using ll = long long;
using ld = long double;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;
using mll = map<ll, ll>;
using qll = queue<ll>;
using P = pair<ll, ll>;
using vp = vector<P>;
using vs = vector<string>;

template <typename T>
inline istream& operator>>(istream& i, vector<T>& v) {
  rep(j, v.size()) i >> v[j];
  return i;
}

template <typename T1, typename T2>
inline istream& operator>>(istream& i, pair<T1, T2>& v) {
  return i >> v.first >> v.second;
}

constexpr ll INF = 0x3f3f3f3f3f3f3f3f;
constexpr ld PI = 3.141592653589793238462643383279;
ll get_digit(ll x) {
  return to_string(x).size();
}

ll gcd(ll x, ll y) {
  return y ? gcd(y, x % y) : x;
}

ll lcm(ll a, ll b) {
  return a / gcd(a, b) * b;
}

template <class T>
bool chmax(T& a, const T& b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}

template <class T>
bool chmin(T& a, const T& b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}

signed main() {
  init();
  ll N, K;
  cin >> N >> K;
  vp A(N);
  cin >> A;

  map<ll, ll> m1, m2;
  rep(i, N) {
    m1[A[i].first]++;
    m2[A[i].second]++;
  }

  ll ans = INF;
  for (auto x1 : m1)
    for (auto y1 : m2)
      for (auto x2 : m1)
        for (auto y2 : m2) {
          //  rep(i, N) rep2(j, i + 1, N) {
          // ll l = min(A[i].first, A[j].first);
          // ll r = max(A[i].first, A[j].first);
          // ll d = min(A[i].second, A[j].second);
          // ll u = max(A[i].second, A[j].second);
          ll l = min(x1.first, x2.first);
          ll r = max(x1.first, x2.first);
          ll d = min(y1.first, y2.first);
          ll u = max(y1.first, y2.first);

          ll count = 0;
          rep(k, N) if (l <= A[k].first and A[k].first <= r and
                        d <= A[k].second and A[k].second <= u) count++;
          if (count >= K) {
            // debug(count);
            // debug(r);
            // debug(l);
            // debug(d);
            // debug(u);
            // debug(r - l);
            // debug(u - d);

            chmin(ans, (r - l) * (u - d));
          }
        }
  ANS;
  return 0;
}

Measured memory_bytes: 3672