module Yuki

open System


let solve ss =
    let num2Lis n =
        let rec f acc x =
            if x >= 10L then 
                f ((x % 10L) :: acc ) (x / 10L)
            else
                x :: acc
        f [] n

    let horoscope n =
        let rec f =
            function
            | [] -> failwith ""
            | x :: [] -> x
            | xs ->
                let ns =
                    xs
                    |> List.pairwise
                    |> List.map ((fun (a, b) -> a + b) >> num2Lis >> List.sum)
                f ns                        
        let ns = num2Lis n
        f ns    

    let ns = ss |> List.map int64
    ns |> List.map horoscope    
    
let T = Console.ReadLine() |> int
let S = List.init T (fun _ -> Console.ReadLine())

solve S
|> List.iter Console.WriteLine