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: Time Limit Exceeded)

using System;
using System.Collections.Generic;

class program
{
    public static void Main()
    {
        var N = int.Parse(Console.ReadLine());
        var elements = new List<long>();
        var max = (long)0;
        for (var i = 0; i < N; i++)
        {
            var num = long.Parse(Console.ReadLine());
            elements.Add(num);
            max = max > num ? max : num;
        }
        var count = 0; var prime = 2;
        while (true)
        {
            for (var i = 2; i <= prime; i++)
            {
                if (i == prime)
                {
                    if (elements.Contains(prime))
                    {
                        count++;
                    }
                }
                else if (prime % i == 0)
                {
                    break;
                }
            }
            if (prime == max)
            {
                break;
            }
            prime++;
        }
        Console.WriteLine(count);
    }
}