fn pangrams(s: &str) -> String {
    let alphabet = "abcdefghijklmnopqrstuvwxyz";
    let tested: HashSet<char> = s
        .to_ascii_lowercase()
        .chars()
        .filter(|x| x.is_ascii_alphabetic())
        .collect();

    if alphabet.chars().all(|x| tested.contains(&x)) {
        return "pangram".into();
    }
    "not pangram".into()
}