let s = read_line()

let rec f i b =
  try
    let c = s.[i] in
    if b then
      begin
        if c <> 'h' then "No"
        else f (i+1) false
      end
    else
      if c = 'i' then f (i+1) true
      else "No"
  with Invalid_argument _ -> if b then "Yes" else "No"

let () = print_endline (f 0 true)
