Scanf.scanf "%d" (fun n ->
    let h = Array.make 1000 0 in
    for i = 1 to n do
        Scanf.scanf " %s" (fun s ->
            let q = String.length s - 2 in
            h.(q) <- h.(q) + 1
        )
    done;
    let rec loop i mx mi =
        if i = 0 then mi else
            if h.(i) > mx then loop (i - 1) h.(i) i
                          else loop (i - 1) mx mi
    in
    loop 999 0 0 |> Printf.printf "%d\n"
)