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: Wrong Answer)

#include <stdio.h>

#include<string.h>

int main()
{ long int sum = 0;
  long int N;
  long int M;
  int flag = 1;
  scanf("%ld %ld\n",&N,&M);
  long int H[N];
  for(long int i=0;i<N;i++){
      scanf("%ld ",&H[i]);
      
  }
  long int R[M][2];
  scanf("\n");
  for(long int i=0;i<N;i++){
      scanf("%ld %ld\n",&R[i][0],&R[i][1]);
  }
  for(long int j=0;j<N;j++ ){
      flag = 1;
      for(long int k=0;k<M;k++){
          if(R[k][0]==(j+1)||R[k][1]==(j+1)){
              flag = 0;
              break;
          }
      }
      if(flag==1){
          sum = sum +1;
          continue;
      }
  }
  for(long int j=0;j<N;j++){
      int yo = 1;
      for(long int k=0;k<M;k++){
          if(R[k][0]==(j+1)){
              if(H[j]>H[(R[k][1])])
              continue;
              else{
                  yo = 0;
                  break;
              }
          }
          if(R[k][1]==(j+1)){
              if(H[j]>H[(R[k][0])])
              continue;
              else{
                  yo = 0;
                  break;
              }
          }
          
      }
      if(yo==1){
          sum = sum + 1;
          continue;
      }
      
  }
  printf("%ld",sum);
}