let is_solution m =
  let rec inner n =
    if m mod n = 0 then true
    else if n = 1 then false
    else inner (n - 1)
  in inner (m-1)

let solve n = 
  let rec inner m =
    if is_solution m then m
    else inner m - 1
  in print_int @@ inner (n + 100)

let _ =
  let n = int_of_string @@ read_line () in
  solve n