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 Kotlin (judge verdict: Accepted)

import java.lang.Math.floor
import java.lang.Math.sqrt

/**
 * @author karayuu
 */
fun main(args: Array<String>) {
  val n = readLine()!!.toInt()
  var count = 0
  (1..n).forEach {
    if (素数かどうか判定(readLine()!!.toInt())) {
      count++
    }
  }

  println(count)
}

fun 素数かどうか判定(x: Int): Boolean {
  if (x == 2) return true
  if (x < 2 || x % 2 == 0) return false
  for (i in 3..floor(sqrt(x.toDouble())).toInt()) {
    if (x % i == 0) {
      return false
    }
  }
  return true
}