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>

int judge(int);
int main(){

  int n,i,cnt=0,*a;

  scanf("%d",&n);
  a=(int *)malloc(sizeof(int)*n);

  for(i=0;i<n;i++){
    scanf("%d",&a[i]);
    if(judge(a[i])==1) cnt++;
  }
  free(a);
  printf("%d\n",cnt);
  return 0;
}

int judge(int a){
  int i;

  if((a==2)||(a==3)||(a==5)) return 1;
  if(a%2==0) return 0; 
  for(i=3;i<=(int)sqrt(a);i+=2){
    if(a%i==0) return 0;
  }
  return 1;
}