N, K = gets.split.map(&:to_i)
S = gets.chomp

left, right = [], []
S.chars.each.with_index do |s, i|
  left << i + 1 if s == "("
  right << i + 1 if s == ")"
end

left.reverse.zip(right) do |l, r|
  if l == K
    puts r
    break
  end
  if r == K
    puts l
    break
  end
end