fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
    if x.len() > y.len() {
        x
    } else {
        y
    }
}

fn main() {
    {
        let x = String::from("3");
        let z2;
        {
            let y = String::from("40");

            let z = longest(&x, &y);
            z2 = longest(&x, &y);

            println!("{:?}", z);
        }
        println!("{:?}", z2);
    }
}