#include <bits/stdc++.h>
using namespace std;
const long long infl = 0x3f3f3f3f3f3f3f3fLL;
const long long infi = 0x3f3f3f3f;
const long long mod = infl;
long long mygcd(long long a, long long b) {
  if (b == 0) {
    return a;
  }
  return mygcd(b, a % b);
}
long long mypow(long long a, long long b) {
  long long res = 1;
  while (b) {
    if (b & 1) res = (res * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return res;
}
void solve() {
  long long n, d;
  cin >> n >> d;
  vector<long long> pro(n);
  for (long long i = 1; i < n - 1; i++) {
    cin >> pro[i];
  }
  vector<vector<long long>> gr(n);
  for (long long i = 0; i < n; i++) {
    long long x, y;
    cin >> x >> y;
    gr[i] = {x, y};
  }
  auto isok = [&](long long x) {
    vector<long long> best(n, -1);
    best[0] = x;
    queue<long long> q;
    q.push(0);
    while (q.size()) {
      long long front = q.front();
      q.pop();
      for (long long i = 1; i < n; i++) {
        if (i == front) {
          continue;
        }
        long long need =
            d * (abs(gr[front][0] - gr[i][0]) + abs(gr[front][1] - gr[i][1]));
        if (need > best[front]) {
          continue;
        }
        long long new_best = best[front] - need + pro[i];
        if (new_best > best[i]) {
          best[i] = new_best;
          q.push(i);
        }
      }
    }
    if (best[n - 1] == -1) {
      return false;
    }
    return true;
  };
  long long l = 0;
  long long r = infi;
  while (l < r) {
    long long m = (l + r) / 2;
    if (isok(m)) {
      r = m;
    } else {
      l = m + 1;
    }
  }
  cout << r << '\n';
}
signed main() {
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(20);
  cin.tie(NULL);
  long long t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
