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 C++14 (judge verdict: Accepted)

#include <cmath>
#include <iostream>

bool isPrime(int x) {
  if (x < 2) return false;
  if (x == 2) return true;
  if (x % 2 == 0) return false;

  double sqrtNum = sqrt(x);
  for (int i = 3; i <= sqrtNum; i += 2) {
    if (x % i == 0) {
      return false;
    }
  }
  return true;
}

int main() {
  int n, cnt = 0;
  std::cin >> n;
  while (n-- > 0) {
    int x;
    std::cin >> x;
    if (isPrime(x)) cnt++;
  }
  std::cout << cnt << std::endl;
  return 0;
}