#include <bits/stdc++.h>
using namespace std;
const int maxn = 210;
int n, K;
long long x[maxn], y[maxn];
pair<int, long long> f[maxn][maxn];
int main() {
  scanf("%d %d", &n, &K), K++;
  for (int i = 1; i <= n; i++) {
    scanf("%lld %lld", &x[i], &y[i]);
  }
  auto cross = [&](int i, int j, int k) {
    long long x1 = x[j] - x[i], y1 = y[j] - y[i];
    long long x2 = x[k] - x[i], y2 = y[k] - y[i];
    return x1 * y2 - x2 * y1;
  };
  auto chk = [&](long long x) {
    for (int len = 3; len <= n; len++) {
      for (int l = 1, r = len; r <= n; l++, r++) {
        f[l][r] = {-1e9, 0};
        for (int k = l + 1; k < r; k++) {
          int a = f[l][k].first + f[k][r].first;
          long long b = f[l][k].second + f[k][r].second + cross(l, k, r);
          if (b >= x) a++, b = 0;
          f[l][r] = max(f[l][r], make_pair(a, b));
        }
      }
    }
    return f[1][n].first >= K;
  };
  long long l = 0, r = 1e17, ans;
  while (l <= r) {
    long long mid = (l + r) / 2;
    chk(mid) ? l = (ans = mid) + 1 : r = mid - 1;
  }
  printf("%lld\n", ans);
  return 0;
}
