let s = read_line () in
let n = String.length s in
let rec loop i =
    if i = n then true else (
        match i mod 2, s.[i] with
        | 0, 'h'
        | 1, 'i' -> loop (i + 1)
        | _ -> false
    )
in
(if loop 0 then "Yes" else "No") |> print_endline