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

fn count_divisors(n : usize) -> usize {
    let mut cnt = 0;
    for i in 1..(n + 1) {
        if n % i == 0 {
            cnt += 1;
        }
    }
    cnt
}
fn main() {
    let stdin = io::stdin();
    let mut buf = String::new();
    stdin.read_line(&mut buf).ok();
    let mut it = buf.split_whitespace().map(|n| usize::from_str(n).unwrap());
    let n = it.next().unwrap();
    let mut ans = 0;
    for i in 1..(n + 1) {
        if i % 2 == 1 && count_divisors(i) == 8 { ans += 1; }
    }
    println!("{}", ans);
}