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 Ruby (judge verdict: Accepted)


def geta(n=0)
  return $stdin.gets.to_i if n==0
  ar = []
  n.times do 
    ar << $stdin.gets.chomp.split
  end
  return ar.flatten(1) if n<=1
  return ar
end

def jadge(n)
  sqrt = Math.sqrt(n).ceil
  2.step(sqrt) do |i|
    return 0 if n%i == 0
  end
  return 1
end

n = geta(0)
ar = geta(n)

cnt = 0
ar.flatten.map(&:to_i).each do |n|
  cnt += 1 if n == 2
  next if n <= 2
  cnt += jadge(n)
end

p cnt