#include <bits/stdc++.h>
using namespace std;
long long f[200][200], a[200], x[200], y[200], d;
int n;
long long dist(int i, int j) { return abs(x[i] - x[j]) + abs(y[i] - y[j]); }
int main() {
  cin >> n >> d;
  for (int i = 2; i <= n - 1; i++) cin >> a[i];
  for (int i = 1; i <= n; i++) cin >> x[i] >> y[i];
  memset(f, 61, sizeof(f));
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++)
      if (i != j) f[i][j] = dist(i, j) * d - a[i];
  for (int i = 1; i <= n; i++) f[i][i] = 0;
  for (int k = 1; k <= n; k++)
    for (int i = 1; i <= n; i++)
      for (int j = 1; j <= n; j++) f[i][j] = min(f[i][j], f[i][k] + f[k][j]);
  if (f[1][n] <= 0)
    cout << 0;
  else
    cout << f[1][n];
  return 0;
}
