import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

N,K = map(int,readline().split())
S = read().rstrip().decode()

stack = [(-1,'$')]
pair = dict()
for i,s in enumerate(S,1):
    if s == ')' and stack[-1][1] == '(':
        j = stack[-1][0]
        pair[i] = j
        pair[j] = i
        stack.pop()
    else:
        stack.append((i,s))

answer = pair[K]
print(answer)