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 main(){
  int n;
  int i,count1=0,count2=0; //count1:入力したnの個数 count2:合成数の個数

  while(scanf("%d",&n)!=EOF){
    count1++;
    if(n!=2 && n%2==0){
      count2++;//2以外の偶数を除く
      continue;
    }
    for(i=3;i<=sqrt(n);i+=2){
      if(n%i==0){
	count2++;
	break;
      }
    }
  }
  printf("%d\n",count1-count2);

  return 0;
}

// xが合成数ならば、√x以下の約数を持つことを利用した