#include <bits/stdc++.h>
using namespace std;
const int MX = 1000;
int dp[MX][MX], a[MX], x[MX], y[MX], n, d;
int dis(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; i++) cin >> a[i];
  for (int i = 1; i <= n; i++) cin >> x[i] >> y[i];
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= n; j++) {
      if (i != j) dp[i][j] = dis(i, j) * d - a[i];
    }
  for (int k = 1; k <= n; k++)
    for (int i = 1; i <= n; i++)
      for (int j = 1; j <= n; j++)
        if (dp[i][j] > dp[i][k] + dp[k][j]) dp[i][j] = dp[i][k] + dp[k][j];
  cout << dp[1][n] << endl;
  return 0;
}
