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: Runtime Error)

#!/usr/bin/env ruby
N = 10_000_000 # ??¢?´¢???????´???°?????????
elt = Array.new(N, 1)
primes = []


# ??¨????????????????????????
elt[0] = 0
elt[1] = 0

N.times do |i|
  next if elt[i].zero?
  primes << i
  k = i * 2
  while k < N
    elt[k] = 0
    k += i
  end
end

n = gets.chomp.to_i

cnt = 0
n.times do
  cnt += 1 unless elt[gets.chomp.to_i].zero?
end

puts cnt