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,sum = 0,i,a[10000];

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

  for(i = 0;i < n;i++)
    {
      if(isprime(a[i]) == 0) continue;
      if(isprime(a[i]) == 1) sum++;
    }
  printf("%d\n",sum);
  return 0;
}
int isprime(int x)
{
  int i;
  double a;
  
  if(x == 2) return 1;

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

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