Problem:
Score: 200 points

Problem Statement

The number 105 is quite special - it is odd but still it has eight divisors.
Now, your task is this: how many odd numbers with exactly eight positive divisors are there between 1 and N (inclusive)?

Constraints

N is an integer between 1 and 200 (inclusive).

Input

Input is given from Standard Input in the following format:

N

Output

Print the count.

Sample Input 1

105

Sample Output 1

1

Among the numbers between 1 and 105, the only number that is odd and has exactly eight divisors is 105.

Sample Input 2

7

Sample Output 2

0

1 has one divisor. 3, 5 and 7 are all prime and have two divisors. Thus, there is no number that satisfies the condition.

Solution in Ruby (2.3.3) (judge verdict: Accepted)

require "prime"
A = Prime.each(30).to_a.select{|v|v>2}

n = gets.to_i
ans = 0
A.permutation(2) do |i,j|
    if i ** 3 * j <= n
        ans += 1 
    end
end
A.combination(3) do |i,j,k|
    if i * j * k <= n
        ans += 1 
    end
end
puts ans