Scanf.scanf "%d %d" (fun n m ->
    let s = Array.init n (fun _ -> Scanf.scanf " %s" (fun s -> s)) in
    let contains s =
        let rec loop i =
            if i > m - 4 then false else
                if String.sub s i 4 = "LOVE" then true else loop (i + 1)
        in
        loop 0
    in
    let rec loop i =
        if i = n then "NO" else
            if contains s.(i) then "YES" else
                loop (i + 1)
    in
    print_endline @@ loop 0
)