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 Go (1.6) (judge verdict: Accepted)

package main

import "fmt"

func main() {
	var N int
	fmt.Scan(&N)
	ans := 0
	for i := 1; i <= N; i += 2 {
		if len(enumDiv(i)) == 7 {
			ans++
		}
	}
	fmt.Println(ans)
}

func enumDiv(x int) (ret []int) {
	ret = []int{}
	upperRet := []int{}
	for i := 1; i*i <= x; i++ {
		if x%i == 0 {
			ret = append(ret, i)
			if i != 1 && i*i != x {
				upperRet = append(upperRet, x/i)
			}
		}
	}
	ret = append(ret, upperRet...)
	return
}