module Yuki

open System

let solve ss =
    let inline str2Lis (str : string) =
        str.ToCharArray()
        |> Array.map (string >> int)
        |> Array.toList

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

    let horoscope (str : string) =
        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 = str2Lis str
        f ns    

    ss
    |> List.map horoscope

let T = Console.ReadLine() |> int
let S = List.init T (fun _ -> Console.ReadLine())

solve S
|> List.iter Console.WriteLine