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 (1.15.1) (judge verdict: Accepted)

use std::*;

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

fn read_vec<T: str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|a| a.parse().ok().unwrap())
        .collect()
}

fn read_vec2d<T: str::FromStr>(n: u32) -> Vec<Vec<T>> {
    (0..n).map(|_| read_vec()).collect()
}

fn digit(n: u32) -> u32 {
    if n < 10 {
        1
    } else {
        digit(n / 10) + 1
    }
}

fn has_8_div(n: u32) -> bool {
    let mut div = 2;
    for i in 2..(n / 2 + 1) {
        if n % i == 0 {
            div += 1;
        }
        if div > 8 {
            break;
        }
    }

    return div == 8;
}

fn main() {
    let n: u32 = read();
    let mut count = 0;
    let mut i = 105;

    while i <= n {
        if has_8_div(i) {
            count += 1;
        }
        i += 2;
    }

    println!("{}", count);
}