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>
int isprime(int);

int main(){
  int n,x,i,c=0;
  scanf("%d",&n);
  for(i = 0;i < n;i++){
    scanf("%d",&x);
    if(isprime(x)){
      c++;
    }
  }
  printf("%d\n",c);
  return 0;
}

int isprime(int x){
  int i;
  if(x<2){
    return 0;
  }
  else if(x == 2){
    return 1;//2 is prime number
  }
  if(x%2 == 0){
    return 0;//not prime number
  }
  for(i = 3;i*i <= x;i++){//i???x??????????????\?????????
    if(x%i == 0){
      return 0;
    }
  }
  return 1;
}