#include <bits/stdc++.h>
using namespace std;
const int N = 105;
long long g[N][N], f[N][N], a[N], d;
int n;
pair<int, int> p[N];
void FloydWarshall() {
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) f[i][j] = g[i][j];
    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]);
      }
    }
  }
}
int main() {
  scanf("%d%lld", &n, &d);
  for (int i = 2; i < n; i++) scanf("%lld", &a[i]);
  for (int i = 1; i <= n; i++) scanf("%d%d", &p[i].first, &p[i].second);
  for (int i = 2; i < n; i++) {
    for (int j = 1; j <= n; j++) {
      if (i == j) continue;
      g[i][j] -= a[i];
    }
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      if (i == j) continue;
      g[i][j] +=
          1ll * d *
          (abs(p[i].first - p[j].first) + abs(p[i].second - p[j].second));
    }
  }
  FloydWarshall();
  printf("%lld", f[1][n]);
  return 0;
}
