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;

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

        int cnt = 0;
        for (int i = 0; i < n; i++) {
            if (IsPrime(int.Parse(Console.ReadLine()))) {
                cnt++;
            }
        }

        Console.WriteLine(cnt);
    }

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

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