let b = 
    let R () = 
        let t = stdin.ReadLine().Split() |> Array.map int
        (t.[0], t.[1])
    [|'A' .. 'C'|]
    |> Array.map (fun c -> 
        let (w, h) = R()
        (c, w, h))
    
b
|> Array.sortWith(fun (_, h, w) (_, h', w')->
    let isSameHeight = h = h'
    let compareByHeight =
        if   h > h' then -1
        elif h = h' then  0
        else 1
    let compareByWeight =
        if   w < w' then -1
        elif w = w' then  0
        else 1
    if isSameHeight then 
        compareByWeight
    else
        compareByHeight)
|> Array.iter(fun (c,_,_) -> printfn "%c" c)