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: Runtime Error)

import java.util.Scanner;

public class Main {

	public static String Y = "Yes";
	public static String N = "No";
	public static String I = "IMPOSSIBLE";
	public static String B = "Bad";
	public static String G = "Good";
	public static long MOD = (long) (Math.pow(10, 9) + 7);
	public static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {

		int n = ni();
		int m = ni();

		long h[] = new long[n];
		boolean ab[][] = new boolean[m][m];
		int b[] = new int[m];

		for (int i = 0; i < n; i++) {
			h[i] = nl();
		}

		boolean yoi[] = new boolean[n];
		for (int a = 0; a < n; a++) {
			yoi[a] = true;
		}

		for (int i = 0; i < m; i++) {

			int a1 = ni() - 1;
			int b1 = ni() - 1;

			if (h[a1] < h[b1]) {
				yoi[a1] = false;
				yoi[b1] = true;
			} else if (h[a1] > h[b1]) {
				yoi[a1] = true;
				yoi[b1] = false;
			} else {
				yoi[a1] = false;
				yoi[b1] = false;
			}

		}

		int count = 0;
		for (boolean flg : yoi) {
			if (flg)
				count++;
		}

		out(count);

	}

	public static int count(String search, String text) {
		int nsearch = search.length();
		int ntext = text.length();
		int count = 0;

		for (int i = 0; i <= ntext - nsearch + 1; i++) {
			for (int j = i + nsearch - 1; j < ntext; j++) {
				if (search.equals(text.substring(i, j + 1))) {
					count++;
				}
			}
		}

		return count;
	}

	/*
	 * 以下メソッド集
	 */
	static int ni() {
		return sc.nextInt();
	}

	static long nl() {
		return sc.nextLong();
	}

	static String n() {
		return sc.next();
	}

	static char[] nc() {
		return sc.next().toCharArray();
	}

	static int kaijo(int n) {
		if (n == 0 || n == 1) {
			return 1;
		} else {
			return n * kaijo(n - 1);
		}
	}

	static int fib(int n) {
		return (n == 1 || n == 0) ? n : fib(n - 2) + fib(n - 1);
	}

	static long lcm(long m, long n) {

		return m * n / gcd(m, n);
	}

	static int lcm(int m, int n) {

		return m * n / gcd(m, n);
	}

	static long gcd(long a, long b) {
		return (b == 0) ? a : gcd(b, a % b);
	}

	static int gcd(int a, int b) {
		return (b == 0) ? a : gcd(b, a % b);
	}

	static void out(String info) {
		System.out.println(info);
	}

	static void out(int info) {
		System.out.println(info);
	}

	static void out(double info) {
		System.out.println(info);
	}

	static void out(long info) {
		System.out.println(info);
	}

	static void out(char info) {
		System.out.println(info);
	}

	static void outn(String info) {
		System.out.print(info);
	}

	static void outn(int info) {
		System.out.print(info);
	}

	static void outn(double info) {
		System.out.print(info);
	}

	static void outn(long info) {
		System.out.print(info);
	}

	static void outn(char info) {
		System.out.print(info);
	}

	static int max(int a, int b) {
		return Math.max(a, b);
	}

	static long max(long a, long b) {
		return Math.max(a, b);
	}

	static int min(int a, int b) {
		return Math.min(a, b);
	}

	static long min(long a, long b) {
		return Math.min(a, b);
	}
}