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<stdlib.h>
#include<math.h>

#define N 10000

int keisan(int);
int main(){
  int i,j,num;
  int S[N];
  int count = 0;
  while(1){
    scanf("%d",&num);
    if(num >= 1 && num <= N)break;
  }
  for(i = 0;i<num;i++){
    scanf("%d", &S[i]);
  }
  for(i = 0;i<num;i++){
    if(keisan(S[i]) == 1)count++;
       }
    printf("%d\n",count);

    return 0;

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