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: Wrong Answer)

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        C solver = new C();
        solver.solve(1, in, out);
        out.close();
    }

    static class C {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            int n = Integer.parseInt(in.next());
            int m = Integer.parseInt(in.next());
            int h[] = new int[n];
            boolean tower[][] = new boolean[n][1];
            for (int i = 0; i < n; i++) {
                h[i] = Integer.parseInt(in.next());
            }
            int load[][] = new int[m * 2][3];
            for (int i = 0; i < m; i++) {
                load[i][0] = Integer.parseInt(in.next()) - 1;
                load[i][1] = Integer.parseInt(in.next()) - 1;
                tower[load[i][0]][0] = true;
                tower[load[i][1]][0] = true;
            }
            for (int i = m; i < m * 2; i++) {
                load[i][0] = load[i - m][1];
                load[i][1] = load[i - m][0];
            }
            int ans = 0;

            for (int j = 0; j < m * 2; j++) {
                if (h[load[j][0]] > h[load[j][1]]) load[j][2]++;
            }

            Set<Integer> tmp = new HashSet<>();
            for (int i = 0; i < m * 2; i++) {
                if (load[i][2] >= 1) tmp.add(load[i][0]);
            }
            ans = tmp.size();
            for (int i = 0; i < n; i++) {
                if (tower[i][0] == false) ans++;
            }

            // 出力
            out.println(ans);

        }

    }
}