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 (GCC 9.2.1) (judge verdict: Accepted)

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<string.h>
//if(strcmp(s[i],"AC")==0)
//if(s[l]=='#')
/*小文字判定
if((moji>= 'a') && (moji<='z')){
    printf("a\n");
    return 0;
  }
  */

int W_Length(char *str){
	int length = 0;
	while(*str++ != '\0')
		length++;
	return length;
}

void swap(long long int *a, long long int *b){
  int temp;
  temp=*a;
  *a=*b;
  *b=temp;
}
//swap(&a, &b)

double deg(double theta){//deg to theta
return theta*(2*3.14159265359)/360;
}

long long int cmp( const void *p, const void *q ) {
    return *(long long int*)p - *(long long int*)q;
}//ちいさい順
//qsort(a,n,sizeof(long long int),cmp);


int cmp_s(const void * left, const void * right)
{
	char *left_char = (char *)left;
  char *right_char = (char *)right;
  return strcmp(left_char, right_char);
}
//qsort(s,n,sizeof(s[0]),cmp_s);
//char s[n][11]

long long int GCD(long long int a, long long int b){
  long long int L=a,S=b;
  while(1){
    if(S>L){
      L=S+L;
      S=L-S;
      L=L-S;
    }
    if(L%S==0){
      return S;
    }
    L=L%S;
  }
  
}

long long int LCM(long long int a, long long int b){
  return a*b/(GCD(a,b));
}

int main (void)
{
	long long int p[5005],b,c,n,i,m,k,h[210000],max,j=1,flag[210000]={0},count=0;
scanf("%lld%lld",&n,&m);
for(i=1;i<=n;i++){
  scanf("%lld",&h[i]);
}  
  for(i=1;i<=m;i++){
    scanf("%lld %lld",&b,&c);
    if(h[b]>=h[c]){
      flag[c]=1;
    }
    if(h[c]>=h[b]){
      flag[b]=1;
    }
  }
  for(i=1;i<=n;i++){
    if(flag[i]==0){
      count++;
    }
  }
  
  printf("%lld",count);
return 0;
}