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 Rust (judge verdict: Accepted)

use std::io::*;

fn main() {
  let stdin = stdin();
  let mut lines = stdin.lock().lines().map(|l| l.unwrap());

  let n = lines.next().unwrap().parse().unwrap();
  let nums = lines.take(n).map(|s| s.parse::<u32>().unwrap());

  let count = nums.filter(|&num| {
    if num == 2 {
      true
    }
    else if num % 2 == 0 {
      false
    }
    else {
      let end = (num as f64).sqrt().floor() as u32;

      for i in (1 .. (end + 1) / 2) {
        if num % (i * 2 + 1) == 0 {
          return false
        }
      }
      true
    }
  }).count();

  println!("{}", count);
}