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 (judge verdict: Accepted)

#include<stdio.h>
#include<math.h>
int isPrime(int x) {
  if(x == 2) return 1;
  if(x < 2 || x%2 == 0) return 0;
  int i = 3;
  while(i <= sqrt((double)x)) {
    if(x%i == 0) return 0;
    i = i + 2;   
  }
  return 1;
}

int main() {
  int i, k, n, count=0;
  scanf("%d", &n);
  int A[n];
  for(i = 0; i < n; i++) {
    scanf("%d", &A[i]);
    k = isPrime(A[i]);
    if(k == 1) count++;
  }
  printf("%d\n", count);
  return 0;
}