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;

namespace ALDS1_1_C{
    class Sample{
        static void Main(string[] args){
            List<int> nums = new List<int>();
            int row = int.Parse(Console.ReadLine());
            while(row>0){
                nums.Add(int.Parse(Console.ReadLine()));
                row--;
            }
            int count=0;
            foreach(int n in nums){
                if(Sosu(n)){
                    count++;
                }
            }
            Console.WriteLine(count);
        }

        static bool Sosu(int num){
            int x = num;
            if(x == 2){
                return true;
            } else if(x<2 || x%2==0){
                return false;
            }

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