Yaroslav is playing a game called "Time". The game has a timer showing the lifespan he's got left. As soon as the timer shows 0, Yaroslav's character dies and the game ends. Also, the game has n clock stations, station number i is at point (x_{i}, y_{i}) of the plane. As the player visits station number i, he increases the current time on his timer by a_{i}. The stations are for one-time use only, so if the player visits some station another time, the time on his timer won't grow.

A player spends d·dist time units to move between stations, where dist is the distance the player has covered and d is some constant. The distance between stations i and j is determined as |x_{i} - x_{j}| + |y_{i} - y_{j}|.

Initially, the player is at station number 1, and the player has strictly more than zero and strictly less than one units of time. At station number 1 one unit of money can increase the time on the timer by one time unit (you can buy only integer number of time units).

Now Yaroslav is wondering, how much money he needs to get to station n. Help Yaroslav. Consider the time to buy and to increase the timer value negligibly small.


-----Input-----

The first line contains integers n and d (3 ≤ n ≤ 100, 10^3 ≤ d ≤ 10^5) — the number of stations and the constant from the statement.

The second line contains n - 2 integers: a_2, a_3, ..., a_{n} - 1 (1 ≤ a_{i} ≤ 10^3). The next n lines contain the coordinates of the stations. The i-th of them contains two integers x_{i}, y_{i} (-100 ≤ x_{i}, y_{i} ≤ 100).

It is guaranteed that no two stations are located at the same point.


-----Output-----

In a single line print an integer — the answer to the problem.


-----Examples-----
Input
3 1000
1000
0 0
0 1
0 3

Output
2000

Input
3 1000
1000
1 0
1 1
1 2

Output
1000

Difficulty: competition

Starter code:

Solutions:
n, d = map(int, input().split())
a = [0] + list(map(int, input().split())) + [0]
x = []
y = []
for i in range(n):
  xx, yy = map(int, input().split())
  x += [xx]
  y += [yy]
b = [-1] * n
b[0] = 0
c = True
while c:
  c = False
  for i in range(n):
    for j in range(1, n):
      if i != j and b[i] != -1:
        t = b[i] + (abs(x[i] - x[j]) + abs(y[i] - y[j])) * d - a[j]
        if b[j] == -1 or t < b[j]:
          b[j] = t
          c = True
print(b[-1])

f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = range(n)
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])

f = lambda: list(map(int, input().split()))
n, d = f()
r = range(n)
a = [0] + f() + [0]
p = [f() for i in r]
s = [1e9] * n
q, s[0] = 1, 0
while q:
    q = 0
    for i in r:
        for j in r:
            if i != j:
                t = s[i] + (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) * d - a[j]
                if t < s[j]: q, s[j] = 1, t
print(s[-1])

f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = list(range(n))
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])


f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = list(range(n))
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])


f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = list(range(n))
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])


f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = list(range(n))
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])


f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = list(range(n))
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])


f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = list(range(n))
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])


f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = list(range(n))
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])


f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = list(range(n))
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])


f = lambda: list(map(int, input().split()))

n, d = f()

a = [0] + f() + [0]

p = [f() for i in range(n)]

r = list(range(n))

s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]

for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]

print(s[-1][0])




# Made By Mostafa_Khaled



R = lambda: map(int, input().split())
n, d = R()
a = [0] + list(R()) + [0]
x = []
y = []
INF = float('inf')

def distance(x1, y1, x2, y2):
    return (abs(x1 - x2) + abs(y1 - y2)) * d

for i in range(n):
  xi, yi = R()
  x += [xi]
  y += [yi]
b = [INF] * n
b[0] = 0
c = True
while c:
  c = False
  for i in range(n):
    for j in range(1, n):
      if i != j and b[i] != -1:
        t = b[i] + distance(x[i], y[i], x[j], y[j]) - a[j]
        if t < b[j]:
          b[j] = t
          c = True
print(b[-1])

R = lambda: map(int, input().split())
n, d = R()
a = [0] + list(R()) + [0]
x = []
y = []
INF = float('inf')
for i in range(n):
  xi, yi = R()
  x += [xi]
  y += [yi]
b = [INF] * n
b[0] = 0
c = True
while c:
  c = False
  for i in range(n):
    for j in range(1, n):
      if i != j and b[i] != -1:
        t = b[i] + (abs(x[i] - x[j]) + abs(y[i] - y[j])) * d - a[j]
        if t < b[j]:
          b[j] = t
          c = True
print(b[-1])

f = lambda: list(map(int, input().split()))
n, d = f()
a = [0] + f() + [0]
p = [f() for i in range(n)]
r = range(n)
s = [[d * (abs(p[i][0] - p[j][0]) + abs(p[i][1] - p[j][1])) - a[j] * (i != j) for j in r] for i in r]
for k in r: s = [[min(s[i][j], s[i][k] + s[k][j]) for i in r] for j in r]
print(s[-1][0])

import sys

def minp():
	return sys.stdin.readline().strip()

def mint():
	return int(minp())

def mints():
	return list(map(int, minp().split()))

def solve():
	n, dc = mints()
	a = list(mints())
	a.append(0)
	x = [0]*n
	y = [0]*n
	for i in range(n):
		x[i], y[i] = mints()
	d = [1<<30]*n
	d[0] = 0
	was = [False]*n
	for i in range(n):
		m = 1<<30
		mi = 0
		for j in range(n):
			if not was[j] and m > d[j]:
				m = d[j]
				mi = j
		j = mi
		was[j] = True
		for k in range(n):
			if not was[k]:
				dd = d[j] + (abs(x[k]-x[j])+abs(y[k]-y[j]))*dc
				dd -= a[k-1]
				if d[k] > dd:
					d[k] = dd
	print(d[-1])

solve()


n, d = list(map(int, input().split()))

a = [0] + list(map(int, input().split())) + [0]      #aumento de timer según estación
X = []
Y = []

for i in range(n):
  x, y = list(map(int, input().split()))                 #Coordenadas de la estación i.
  X.append(x) 
  Y.append(y)

mon = [-1] * n                          #array para el monto necesario para llegar.
mon[0] = 0
Z = 0                                   #valor que permitirá entrar al loop

while Z == 0:
  Z = 1

  for i in range(n):                                  #estamos en estación i

    for j in range(1, n):                             #queremos ir a estación j

      if i != j and mon[i] != -1:                      #si no queremos ir a la misma estación y donde estamos pudimos llegar.
        costo = mon[i] + (abs(X[i] - X[j]) + abs(Y[i] - Y[j]))*d - a[j]         #nuevo costo necesario para ir de i a j.

        if mon[j] == -1 or costo < mon[j]:          #si el nuevo costo es menor que uno anterior, se guarda este o si antes no había ningun costo guardado.
          mon[j] = costo
          Z = 0                              #volvemos a entrar al loop, esto asegura que todos los mon[] van a dejar de ser '1 y tendran un costo.
print(mon[-1])                               #costo de llegar a la última estación.


from sys import stdin
from math import inf


def readline():
    return list(map(int, stdin.readline().strip().split()))


def main():
    n, d = readline()
    a = [0] + list(readline()) + [0]
    x = [0] * n
    y = [0] * n
    for i in range(n):
        x[i], y[i] = readline()
    lower_cost = [inf] * n
    lower_cost[0] = 0
    visited = [False] * n
    for i in range(n - 1):
        lower_value = inf
        position = 0
        for j in range(n):
            if not visited[j] and lower_value > lower_cost[j]:
                lower_value = lower_cost[j]
                position = j
        visited[position] = True
        for k in range(n):
            if not visited[k]:
                diff = lower_cost[position] + d * (abs(x[k] - x[position]) + abs(y[k] - y[position])) - a[position]
                if lower_cost[k] > diff:
                    lower_cost[k] = diff
    return lower_cost[-1]


def __starting_point():
    print(main())

__starting_point()

from sys import stdin
from math import inf


def readline():
    return list(map(int, stdin.readline().strip().split()))


def dijkstra():
    n, d = readline()
    a = [0] + list(readline()) + [0]
    x = [0] * n
    y = [0] * n
    for i in range(n):
        x[i], y[i] = readline()
    lower_cost = [inf] * n
    lower_cost[0] = 0
    visited = [False] * n
    for i in range(n - 1):
        lower_value = inf
        position = 0
        for j in range(n):
            if not visited[j] and lower_value > lower_cost[j]:
                lower_value = lower_cost[j]
                position = j
        visited[position] = True
        for k in range(n):
            if not visited[k]:
                diff = lower_cost[position] + d * (abs(x[k] - x[position]) + abs(y[k] - y[position])) - a[position]
                if lower_cost[k] > diff:
                    lower_cost[k] = diff
    return lower_cost[-1]


def __starting_point():
    print(dijkstra())

__starting_point()

from sys import stdin
from math import inf


def main():
    n, d = readline()
    a = [0] + list(readline()) + [0]
    x = [0] * n
    y = [0] * n
    # parent = [-1] * n  #  In case you want to know the path traveled
    for i in range(n):
        x[i], y[i] = readline()
    return dijkstra(n, d, a, x, y)  # , parent)


def readline():
    return list(map(int, stdin.readline().strip().split()))


def dijkstra(n, d, a, x, y):  # , parent):
    lower_cost = [inf] * n
    lower_cost[0] = 0
    visited = [False] * n
    for i in range(n - 1):
        position = minimum(n, visited, lower_cost)
        visited[position] = True
        for k in range(n):
            if not visited[k]:
                diff = lower_cost[position] + d * (abs(x[k] - x[position]) + abs(y[k] - y[position])) - a[position]
                if lower_cost[k] > diff:
                    lower_cost[k] = diff
                    # parent[k] = position
    return lower_cost[-1]


def minimum(n, visited, lower_cost):
    lower_value = inf
    position = 0
    for j in range(n):
        if visited[j] or lower_value <= lower_cost[j]:
            continue
        lower_value = lower_cost[j]
        position = j
    return position


def __starting_point():
    print(main())

__starting_point()

from sys import stdin
from math import inf


def readline():
    return list(map(int, stdin.readline().strip().split()))


def dijkstra():  # , parent):
    n, d = readline()
    a = [0] + list(readline()) + [0]
    x = [0] * n
    y = [0] * n
    # parent = [-1] * n  #  In case you want to know the path traveled
    for i in range(n):
        x[i], y[i] = readline()
    lower_cost = [inf] * n
    lower_cost[0] = 0
    visited = [False] * n
    for i in range(n - 1):
        lower_value = inf
        position = 0
        for j in range(n):
            if visited[j] or lower_value <= lower_cost[j]:
                continue
            lower_value = lower_cost[j]
            position = j
        visited[position] = True
        for k in range(n):
            if not visited[k]:
                diff = lower_cost[position] + d * (abs(x[k] - x[position]) + abs(y[k] - y[position])) - a[position]
                if lower_cost[k] > diff:
                    lower_cost[k] = diff
                    # parent[k] = position
    return lower_cost[-1]


def __starting_point():
    print(dijkstra())

__starting_point()

from sys import stdin
from math import inf
 
 
def readline():
    return map(int, stdin.readline().strip().split())
 
 
def dijkstra():
    n, d = readline()
    a = [0] + list(readline()) + [0]
    x = [0] * n
    y = [0] * n
    for i in range(n):
        x[i], y[i] = readline()
    lower_cost = [inf] * n
    lower_cost[0] = 0
    visited = [False] * n
    for i in range(n - 1):
        lower_value = inf
        position = 0
        for j in range(n):
            if not visited[j] and lower_value > lower_cost[j]:
                lower_value = lower_cost[j]
                position = j
        if position == n - 1:
            break
        visited[position] = True
        for k in range(n):
            if not visited[k]:
                diff = lower_cost[position] + d * (abs(x[k] - x[position]) + abs(y[k] - y[position])) - a[position]
                if lower_cost[k] > diff:
                    lower_cost[k] = diff
    return lower_cost[-1]
 
 
def __starting_point():
    print(dijkstra())
__starting_point()

from sys import stdin, stdout
from math import inf


def main():
    n, d = readline()
    a = [0] + list(readline()) + [0]
    x = [0] * n
    y = [0] * n
    # parent = [-1] * n  #  In case you want to know the path traveled
    for i in range(n):
        x[i], y[i] = readline()
    return dijkstra(n, d, a, x, y)  # , parent)


def readline():
    return list(map(int, stdin.readline().strip().split()))


def dijkstra(n, d, a, x, y):  # , parent):
    lower_cost = [inf] * n
    lower_cost[0] = 0
    visited = [False] * n
    for i in range(n - 1):
        position = minimum(n, visited, lower_cost)
        if position == n - 1:
            break
        visited[position] = True
        for k in range(n):
            if not visited[k]:
                diff = lower_cost[position] + d * (abs(x[k] - x[position]) + abs(y[k] - y[position])) - a[position]
                if lower_cost[k] > diff:
                    lower_cost[k] = diff
                    # parent[k] = position
    return lower_cost[-1]


def minimum(n, visited, lower_cost):
    lower_value = inf
    position = 0
    for j in range(n):
        if not visited[j] and lower_value > lower_cost[j]:
            lower_value = lower_cost[j]
            position = j
    return position


def __starting_point():
    stdout.write("".join(str(main()) + "\n"))

__starting_point()

from sys import stdin, stdout
from math import inf


def main():
    n, d = readline()
    a = [0] + list(readline()) + [0]
    x = [0] * n
    y = [0] * n
    # parent = [-1] * n  #  In case you want to know the path traveled
    for i in range(n):
        x[i], y[i] = readline()
    return dijkstra(n, d, a, x, y)  # , parent)


def readline():
    return list(map(int, stdin.readline().strip().split()))


def dijkstra(n, d, a, x, y):  # , parent):
    lower_cost = [inf] * n
    lower_cost[0] = 0
    visited = [False] * n
    for i in range(n - 1):
        position = minimum(n, visited, lower_cost)
        if position == n - 1:
            break
        visited[position] = True
        for k in range(n):
            if not visited[k]:
                diff = lower_cost[position] + d * (abs(x[k] - x[position]) + abs(y[k] - y[position])) - a[position]
                if lower_cost[k] > diff:
                    lower_cost[k] = diff
                    # parent[k] = position
    return lower_cost[-1]


def minimum(n, visited, lower_cost):
    lower_value = inf
    position = 0
    for j in range(n):
        if not visited[j] and lower_value > lower_cost[j]:
            lower_value = lower_cost[j]
            position = j
    return position


def __starting_point():
    stdout.write(str(main()) + '\n')

__starting_point()