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)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int cnt = 0;

            for (int i = 0; i < n; i++)
            {
                int input = int.Parse(Console.ReadLine());

                if (IsPrime(input)) cnt++;
            }
            Console.WriteLine(cnt);
        }

        static bool IsPrime(int x)
        {
            if (x < 2) return false;
            if (x == 2) return true;
            if (x % 2 == 0) return false;

            int len = (int)Math.Sqrt(x);
            for (int i = 3; i <= len; i += 2)
            {
                if (x % i == 0) return false;
            }
            return true;
        }
    }
}