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: Time Limit Exceeded)

#include<stdio.h>
int isprime(int x)
{
    int i;
    if(
        x==2||
        x==3||
        x==5||
        x==7||
        x==11||
        x==13||
        x==17||
        x==19
        )return 1;
    else if(
        x==1||
        x%2==0||
        x%3==0||
        x%5==0||
        x%7==0||
        x%11==0||
        x%13==0||
        x%17==0||
        x%19==0
    )return 0;
    for(i=23;i<x;i+=2){
        if(x%i==0)return 0;
    }
    return 1;
}

int main()
{
    int a,b,c=0,i;
    scanf("%d",&a);
    for(i=0;i<a;i++){
        scanf("%d",&b);
        c+=isprime(b);
    }
    printf("%d\n",c);
    return 0;
}