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 C# (Mono-mcs 6.8.0.105) (judge verdict: Accepted)

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;

namespace ABC166
{
    public class Solve
    {
        public static void Main(string[] args)
        {
            new ABC_C();
        }
    }
    public class ABC_A
    {
        public ABC_A()
        {
            var s = Ex.Read;

            var str = s == "ABC" ? "ARC" : "ABC";
            str.Cw();
        }
    }
    public class ABC_B
    {
        public ABC_B()
        {
            var l = Ex.ReadIntArray();
            // N 人のすぬけ君  K 種類のお菓子
            var n = (int)l[0];
            var k = (int)l[1];

            // お菓子を1つも持っていない
            bool[] ans = new bool[n];

            for (int i = 0; i < k; i++)
            {
                var ii = Ex.ReadInt;
                var l2 = Ex.ReadIntArray();
                foreach (var v in l2) ans[v - 1] = true;
            }
            ans.Where(v => !v).Count().Cw();
        }
    }
    public class ABC_C
    {
        public ABC_C()
        {
            var l = Ex.ReadLongArray();
            // N 個の展望台があり、展望台 i の標高は H i です。  M 本の道
            // 道jは展望台Ajと展望台Bjを結んでいます
            var n = l[0];
            var m = l[1];

            var h = Ex.ReadLongArray();

            //展望台 i から一本の道を使って辿り着ける どの展望台よりも展望台 i の方が標高が高い
            //展望台 i から一本の道を使って辿り着ける 展望台が存在しない場合
            bool[] ans = new bool[n];

            for (int i = 0; i < m; i++)
            {
                var lm = Ex.ReadLongArray();
                var a = lm[0] - 1;
                var b = lm[1] - 1;
                if (h[a] <= h[b]) ans[a] = true;
                if (h[a] >= h[b]) ans[b] = true;
            }
            ans.Where(v => !v).Count().Cw();
        }
    }
    public class ABC_D
    {
        public ABC_D()
        {
        }
    }
    public class ABC_E
    {
        public ABC_E()
        {
        }
    }
    public class ABC_F
    {
        public ABC_F()
        {
        }
    }
    public static class Ex
    {
        public static void Cw(this object s) { Console.WriteLine(s); }

        public static List<string> FastSort(this List<string> s) { s.Sort(StringComparer.Ordinal); return s.ToList(); }
        public static string yesno(this bool b) { return b ? "yes" : "no"; }
        public static string YesNo(this bool b) { return b ? "Yes" : "No"; }
        public static string YESNO(this bool b) { return b ? "YES" : "NO"; }

        public static string Read { get { return Console.ReadLine().Trim(); } }
        public static int ReadInt { get { return int.Parse(Read); } }
        public static long ReadLong { get { return long.Parse(Read); } }
        public static double ReadDouble { get { return double.Parse(Read); } }
        public static string[] ReadArray() { return Read.Split(' '); }
        public static int[] ReadIntArray() { return Read.Split(' ').Select(int.Parse).ToArray(); }
        public static long[] ReadLongArray() { return Read.Split(' ').Select(long.Parse).ToArray(); }
        public static string[] ReadArray(long N) { var ret = new string[N]; for (long i = 0; i < N; ++i) ret[i] = Read; return ret; }
        public static int[] ReadIntArray(long N) { var ret = new int[N]; for (long i = 0; i < N; ++i) ret[i] = ReadInt; return ret; }
        public static long[] ReadLongArray(long N) { var ret = new long[N]; for (long i = 0; i < N; ++i) ret[i] = ReadLong; return ret; }
    }
}