n,k=map(int,input().split())
s=input()
l=list(range(1,n+1))

while(len(s)>0):
	x=s.find("()")
	if l[x]==k: print(l[x+1]); break
	if l[x+1]==k: print(l[x]); break
	s=s[:x]+s[x+2:]
	l=l[:x]+l[x+2:]