#!/usr/bin/python
# -*- coding: utf-8 -*-
# †
from __future__ import unicode_literals
import sys, codecs
sys.stdout = codecs.getwriter('utf-8')(sys.stdout)

from collections import deque

N, K = map(int, raw_input().split())
K -= 1
S = raw_input()
stack = deque()
for i, e in enumerate(S):
    if e == '(':
        stack.append(i)
        continue
    sett = set((i, stack.pop()))
    if K in sett:
        print list(sett - set([K]))[0] + 1
        exit(0)
print '(ΦωΦ)'