import strutils, sequtils
let
  t = stdin.readLine.split.map(parseInt)
  (n, k) = (t[0], t[1])
var
  s = stdin.readLine
  i = s.high
  h = 0
  L, R: seq[int] = @[]

while s.count('(') > 0:
  i -= 1
  if s[i] == '(':
    s[i] = ('A'.ord + h).chr
    L.add(i + 1)
    var j = i + 1
    while s[j] != ')': j += 1
    s[j] = ('a'.ord + h).chr
    R.add(j + 1)
    h += 1

if k in L: echo R[L.find(k)]
else: echo L[R.find(k)]