class A
  def initialize
    n, k = gets.chomp.split(' ').map(&:to_i)
    s = gets.chomp.chars

    answer = []
    stack = []

    s.each.with_index(1) do |ch, index|
      if ch == '('
        stack << index
      else
        i = stack.pop
        answer[i] = index
        answer[index] = i
      end
    end

    puts answer[k]
  end
end

A.new