let () =
  let n, k = Scanf.scanf "%d %d " (fun n k -> n, k) in
  let s = Scanf.scanf "%s " (fun i -> i) in
  let a = Array.make (n + 1) 0 in
  String.iteri (fun i c ->
    if c = '(' then a.(i) <- a.(i) + 1 else a.(i+1) <- a.(i+1) - 1) s;
  Array.iteri (fun i e -> if i > 0 then a.(i) <- a.(i) + a.(i-1)) a;
  let k = k - 1 in
  if s.[k] = '(' then
    let rec doit i =
      if i = n then assert false
      else if a.(i) = a.(k) then i + 1
      else doit (i + 1) in
    doit (k + 1) |> Printf.printf "%d\n"
  else
    let rec doit i =
      if i < 0 then assert false
      else if a.(i) = a.(k) then i + 1
      else doit (i - 1) in
    doit (k - 1) |> Printf.printf "%d\n"