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 naturalnumber(int x);
int main(void){

  int A[N], i, n, j, c=0, s;

  scanf("%d",&n);

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

  for(i = 0; i < n; i++){
    s = A[i];
    if(naturalnumber(s) == 1) c++;
  }
  printf("%d\n", c);
  return 0;
}

int naturalnumber(s){
  int j;

  if(s == 2 || s == 3 || s == 5 || s == 7) return 1;
  if(s%2 == 0) return 0;
  for(j = 3; j <= sqrt(s); j += 2){
    if(s%j == 0) return 0;
  }

  return 1;
}