fn slow_square(x : u32) -> Result<u32, i32>  {
    let res = x*x;
    if res > 100 {
        Err(1)
    }
    else{
        Ok(res)
    }
}

fn main(){
    let res : u32 = match slow_square(9) {
        Ok(n) => n,
        Err(_) => {
            println!("Error:  {}", "too big");
            0
        }
    };
    println!("res = {}", res);
}