n, k = gets.split.map(&:to_i)
s = gets.chomp
stack = []
a = Array.new(n)

s.each_char.with_index do |e, idx|
  if stack.dig(-1, 0) == '(' && e == ')'
    x = stack.pop[1]
    a[x] = idx
    a[idx] = x
  else
    stack << [e, idx]
  end
end

puts a[k - 1] + 1