let char_list_of_string str = 
  let rec f0 i a =
    if i<0 then a else f0 (i-1) (str.[i]::a)
	in f0 (String.length str - 1) []
let string_of_char_list ls = 
	List.fold_left (fun u v -> u ^ (String.make 1 v)) "" ls

let () =
	let s = read_line () |> char_list_of_string |> List.rev
	in let hoge a = a|>List.rev|>string_of_char_list
	in let rec f0 a = match a with
	| [] -> "YES"
	|	p::q::r::s::t::u::v::tl when "dreamer" = hoge [p;q;r;s;t;u;v] -> f0 tl
	| p::q::r::s::t::u::tl when "eraser" = hoge [p;q;r;s;t;u] -> f0 tl
	| p::q::r::s::t::tl when let h = hoge [p;q;r;s;t] in "dream" = h || "erase" = h -> f0 tl
	| _ -> "NO"
	in print_endline @@ f0 s