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>

int isPrime(int);

int main()
{
  int n, data[10000], k = 0, i, key;

  /*??\??????????????°????±????*/
  scanf("%d", &n);

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

  for(i = 0; i < n; i++){
    key = isPrime(data[i]);
    if(key == 1)
      k++;
  }
  printf("%d\n", k);
  return 0;
}

int isPrime(int x)
{
  int i;
  if(x == 2)
    return 1;

  if(x < 2 || x % 2 == 0)
    return 0;

  i = 3;
  
  while(i <= sqrt(x)){
    if(x % i == 0)
      return 0;
    i += 2;
  }
  return 1;
}