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 Rust (1.42.0) (judge verdict: Accepted)

use std::io;
use std::str::FromStr;

fn input<T:FromStr>() -> T {
    let mut line: String = String::new();
    io::stdin().read_line(&mut line);
    line.trim().parse().ok().unwrap()
}

fn divisors(n: u64) -> Vec<u64> {
    let mut divisors: Vec<u64> = Vec::new();
    for i in 1..(n+1) {
        if i * i > n {
            break;
        }
        if n % i == 0 {
            divisors.push(i);
            if i * i != n {
                divisors.push(n / i);
            }
        }
    }
    divisors
}

fn main() {
    let n: u64 = input();
    let mut count = 0;
    for i in 1..(n+1) {
        if i % 2 == 1 && divisors(i).len() == 8 {
            count += 1;
        }
    }
    println!("{}", count);
}