n,k=map(int,input().split())
l=list(input())
from collections import deque
s=deque()
ans=[]
for i in range(n):
    if l[i]=="(":
        s.append(i)
    else:
        ans.append([i+1,s.pop()+1])

for x in ans:
    if x[0]==k:
        print(x[1])
        exit()
    elif x[1]==k:
        print(x[0])
        exit()