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)

fn main() {
    let mut sum = 0;
    let n = read::<usize>();

    for _ in 0..n {
        let a = read::<usize>();
        if is_prime(a) {
            sum += 1;
        }
    }

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

fn is_prime(x: usize) -> bool {
    if x == 2 { return true; }
    if x < 2 || x % 2 == 0 { return false; }

    let mut i = 3;
    while i as f64 <= (x as f64).sqrt() {
        if x % i == 0 { return false; }
        i += 2;
    }
    return true
}

/// 標準入力から一行を読み取り、指定の型に変換する関数
fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}