let solve n = 1

let _ =
  let n = Scanf.scanf "%d\n" (fun n -> n) in
  let s = Scanf.scanf "%s\n" (fun s -> s) in
  let k = Scanf.scanf "%d\n" (fun k -> k) in
  let c = String.get s k in
  for i = 0 to n - 1 do
    let c' = String.get s i in
    print_char @@ if c = c' then c else '*'
  done
