let solve n =
  let len_ans = n / 2 in
  let a_arr = Array.make len_ans 1 in
  if n mod 2 = 1 then a_arr.(0) <- 7;
  Array.fold_left (fun a b -> a * 10 + b) 0 a_arr

let () =
  let n = read_line () |> int_of_string in
  solve n
  |> string_of_int
  |> print_endline