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;

class Program
{
    static bool IsPrime(int a)
    {
        if (a == 2)
        {
            return true;
        }
        if (a < 2 || a % 2 == 0)
        {
            return false;
        }
        for (int i = 3; i <= Math.Sqrt(a); i += 2)
        {
            if (a % i == 0)
            {
                return false;
            }
        }
        return true;
    }

    static IEnumerable<int> Input()
    {
        string s;
        while ((s = Console.ReadLine()) != null) 
        {
            yield return int.Parse(s);
        }
    }

    static void Main()
    {
        var ans = Input().Where(x => IsPrime(x)).Count();
        Console.WriteLine(ans);
    }
}