# -*- coding: utf-8 -*-

from collections import deque

class paren:
    def __init__(self, char, id):
        self.char = char
        self.id = id

N, K = map(int, input().split())
S = input()

parentheses = deque()

for (c,i) in zip(S, range(1, len(S)+1)):
    p = paren(c,i)
    if len(parentheses)==0 or c=='(':
        parentheses.append(p)
    else:
        q = parentheses.pop()
        if p.id==K or q.id==K:
            print(q.id if p.id==K else p.id)
            break