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 Scala (judge verdict: Accepted)

import scala.io.Source

object Main{
  def main(args: Array[String]){
    val lines = for{
      in <- Source.stdin.getLines
    }yield if(isPrime(in.toInt)) in else -1

    println(lines.toList.tail.filter(_ != -1).length)
  }

  def isPrime(n: Int): Boolean = (2 to Math.sqrt(n).toInt).forall(n % _ != 0)
}