import java.util.Scanner;

public class Main{

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int count = 0;
        while(sc.hasNext()){
            if(isPrime(sc.nextInt())) count++;
        }
        System.out.println(count);
        sc.close();
    }

    private static boolean isPrime(int x) {
        if(x == 2) return true;
        else if (x < 2 || x % 2 == 0)return false;
        int i = 3;
        while(i <= Math.sqrt(x)){
            if(x % i == 0) return false;
            i = i + 2;
        }
        return true;
    }

}
