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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

using System.Collections;

class Program
{
    static void Main()
    {
        int N = int.Parse(Console.ReadLine());

        //3,5,7,11,13

        
        //3,3,3,5->135
        //3,3,3,7->189
        //3,5,7->105
        //3,5,11->165
        //3,5,13->195

        int[] nums = new int[] { 105, 135, 165, 189, 195 };

        Console.WriteLine(nums.TakeWhile(itm => itm <= N).Count());
    }
}



static class MathUtil
{
    public static IEnumerable<IEnumerable<int>> GetPermutation(int n)
    {
        if (n == 0)
        {
            yield return Single(0);
            yield break;
        }

        for (int i = 0; i <= n; i++)
        {
            foreach (var x in GetPermutation(n - 1))
            {
                yield return Single(i).Concat(x.Select(itm => itm < i ? itm : itm + 1));
            }
        }
    }

    private static IEnumerable<int> Single(int x)
    {
        yield return x;
    }

    public static IEnumerable<int> EnumeratePrimeNumbers()
    {
        List<int> primes = new List<int>() { 2 };
        yield return 2;

        for (int i = 3; i < int.MaxValue; i++)
        {
            bool isPrime = true;
            int Sqrt = (int)Math.Sqrt(i) + 1;

            foreach (var prime in primes)
            {
                if (prime > Sqrt)
                {
                    break;
                }
                if (i % prime == 0)
                {
                    isPrime = false;
                    break;
                }
            }

            if (isPrime)
            {
                primes.Add(i);
                yield return i;
            }
        }
    }
}