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 Prime_Numbers {
	public static void Main() {

		int count = 0;
		string num = Console.ReadLine();
		int n = int.Parse(num);
		int[] a = new int[n];

		for(int i = 0; i < n; i++) {
			a[i] = int.Parse(Console.ReadLine());
		}

		for(int i = 0; i < n; i++) {
			if(Prime(a[i])) {
				count++;
			}
		}

		Console.WriteLine(count);

	}

	static bool Prime(int n) {

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

		return true;

	}

}