Problem:
Score : 300 points

Problem Statement

There are N observatories in AtCoder Hill, called Obs. 1, Obs. 2, ..., Obs. N. The elevation of Obs. i is H_i.
There are also M roads, each connecting two different observatories. Road j connects Obs. A_j and Obs. B_j.

Obs. i is said to be good when its elevation is higher than those of all observatories that can be reached from Obs. i using just one road.
Note that Obs. i is also good when no observatory can be reached from Obs. i using just one road.

How many good observatories are there?

Constraints

2 \leq N \leq 10^5

1 \leq M \leq 10^5

1 \leq H_i \leq 10^9

1 \leq A_i,B_i \leq N

A_i \neq B_i

Multiple roads may connect the same pair of observatories.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M
H_1 H_2 ... H_N
A_1 B_1
A_2 B_2
:
A_M B_M

Output

Print the number of good observatories.

Sample Input 1

4 3
1 2 3 4
1 3
2 3
2 4

Sample Output 1

2

From Obs. 1, you can reach Obs. 3 using just one road. The elevation of Obs. 1 is not higher than that of Obs. 3, so Obs. 1 is not good.

From Obs. 2, you can reach Obs. 3 and 4 using just one road. The elevation of Obs. 2 is not higher than that of Obs. 3, so Obs. 2 is not good.

From Obs. 3, you can reach Obs. 1 and 2 using just one road. The elevation of Obs. 3 is higher than those of Obs. 1 and 2, so Obs. 3 is good.

From Obs. 4, you can reach Obs. 2 using just one road. The elevation of Obs. 4 is higher than that of Obs. 2, so Obs. 4 is good.

Thus, the good observatories are Obs. 3 and 4, so there are two good observatories.

Sample Input 2

6 5
8 6 9 1 2 1
1 3
4 2
4 3
4 6
4 6

Sample Output 2

3

Solution in Python (3.8.2) (judge verdict: Wrong Answer)

N,M = map(int, input().split())
H = list(map(int, input().split()))
import copy
max_H = copy.deepcopy(H)
max_ind = [0]*N

for _ in range(M):
  a,b = map(int, input().split())
  # path[a] += [b]
  if max_H[a-1] > H[b-1]:
    # max_H[a-1] = H[a-1]
    # print("A: {} {} H: {}".format(a-1, b-1, H[a-1]))
    if max_ind[a-1]==0:
      max_ind[a-1]=a-1
  elif max_H[a-1] < H[b-1]:
    max_H[a-1]=H[b-1]
    # print("B: {} {} H: {}".format(a-1, b-1, H[b-1]))
    max_ind[a-1]=b-1
  else:
    max_ind[a-1]=-1
  
  if max_H[b-1] > H[a-1]:
    # max_H[b-1]=H[b-1]
    # print("C: {} {} H: {}".format(a-1, b-1, H[b-1]))
    if max_ind[b-1]==0:
      max_ind[b-1]=b-1
  elif max_H[b-1] < H[a-1]:
    max_H[b-1]=H[a-1]
    # print("D: {} {} H: {}".format(a-1, b-1, H[a-1]))
    max_ind[b-1]=a-1
  else:
    max_ind[b-1]=-1

s = set(max_ind)
n = len(s)
if -1 in s:
  n -= 1

if 0 in s:
  n -=1
  n += max_ind.count(0)

print(n)
# print(max_ind)