Problem:
Prime Numbers

A prime number is a natural number which has exactly two distinct natural number divisors: 1 and itself. For example, the first four prime numbers are: 2, 3, 5 and 7.

Write a program which reads a list of N integers and prints the number of prime numbers in the list.

Input

The first line contains an integer N, the number of elements in the list.

N numbers are given in the following lines.

Output

Print the number of prime numbers in the given list.

Constraints

1 ≤ N ≤ 10000

2 ≤ an element of the list ≤ 108

Sample Input 1

5
2
3
4
5
6

Sample Output 1

3

Sample Input 2

11
7
8
9
10
11
12
13
14
15
16
17

Sample Output 2

4

Solution in C (judge verdict: Accepted)

#include<stdio.h>
#include<math.h>

#define N 10000
int main(){
  int n,A[N],i,j,count=0,flag,k1;
  double k2;

  scanf("%d",&n);

  for(i=0;i<n;i++) scanf("%d",&A[i]);

  for( j = 0 ; j < n ; j++ ){
    flag = 0;
    if( A[j] != 2){
      if( A[j]%2 == 1){
	k2 = sqrt(A[j]);
	k1 = ceil(k2);
	for( i = 2 ; i <= k1 ; i++ ) {
	  if( A[j] % i == 0 ) {
	    flag = 1;
	    break;
	  }
	}
	if( flag == 0 ) count++;
      }
    }
    else count++;
  }
  printf("%d\n",count);
  return 0;
}