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;

namespace aoj
{
    class Program
    {
        static void Main(string[] args)
        {
            var count = 0;
            var length = int.Parse(Console.ReadLine());
            for (var i = 0; i < length; ++i)
            {
                var input = int.Parse(Console.ReadLine());
                if (IsPrime(input))
                {
                    ++count;
                }
            }

            Console.WriteLine(count);
        }
        
        static bool IsPrime(int _num)
        {
            if (_num == 2) { return true; }

            if (_num < 2 || _num % 2 == 0) { return false; }

            for (var i = 3; i <= Math.Sqrt(_num); i += 2)
            {
                if (_num % i == 0) { return false; }
            }

            return true;
        }
    }
}