Scanf.scanf "%d %d" (fun n m ->
    let rec loop i c =
        if i = m then c else
            let c = Scanf.scanf " %d %d" (fun p q ->
                if p = c then q else
                if q = c then p else c
            )
            in
            loop (i + 1) c
    in
    loop 0 n |> Printf.printf "%d\n"
)