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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

class Main {



    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
            int n =sc.nextInt();
            int m =sc.nextInt();
            int arr[]=new int[n];

            for(int i=0;i<n;i++)
            {
                arr[i]=sc.nextInt();
            }
            int checkArr[] =new int[n];

            for(int i=-0;i<m;i++)
            {
                int a =sc.nextInt()-1;
                int b=sc.nextInt()-1;
                if(arr[b]>arr[a])
                {
                    checkArr[a]=-1;
                }
                else if(arr[a]>arr[b])
                {
                    checkArr[b]=-1;
                }
                else
                {
                    checkArr[a]=-1;
                    checkArr[b]=-1;
                }
            }
            int count =0;
            for(int i=0;i<n;i++)
            {
                if(checkArr[i]!=(-1))
                {
                    count=count+1;
                }
            }
            System.out.println(count);

    }


}