#[allow(non_upper_case_globals)]
static the_Ultimate_Question_of_Life_the_Universe_and_Everything: &str =
"What do you get if you multiply 6 by 9?";

fn foo() -> i32 {
    // std::thread::sleep(std::time::Duration::from_secs_f64(60. * 60. * 24. * 365.25 * 10_000_000.));
    decimal_to_base_13(
        the_Ultimate_Question_of_Life_the_Universe_and_Everything
        .split(|c: char| !c.is_ascii_digit())
        .filter_map(|s| s.parse::<i32>().ok())
        .product()
    )
}

fn decimal_to_base_13(decimal: i32) -> i32 {
    let mut result = String::new();
    let mut remainder = decimal;
    while remainder > 0 {
        let digit = remainder % 13;
        remainder /= 13;
        result.insert_str(0, match digit {
            0 => "0",
            1 => "1",
            2 => "2",
            3 => "3",
            4 => "4",
            5 => "5",
            6 => "6",
            7 => "7",
            8 => "8",
            9 => "9",
            _ => unreachable!(),
        });
    }
    result.parse().unwrap()
}