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>
#define N 10000
int primenum(int);
int main(){
  int a[N],b,i,num=0;
  scanf("%d",&b);
  for(i=0;i<b;i++){
    scanf("%d\n",&a[i]);
  }
  for(i=0;i<b;i++){
    if(primenum(a[i]))
      num++;
  }
  printf("%d\n",num);
  return 0;
}

int primenum(int c){
  int j;
  if(c==2)return 1;
  if(c%2==0 || c<2)return 0;
  j=3;
  while(j<=(int)sqrt(c)){
    if(c%j==0)return 0;
    j+=2;
  }
  return 1;
}