n, k = gets.chomp.split(" ").map(&:to_i)
s = gets.chomp.split("")
left = []
paren = {}
s.each_with_index do |i, j|
  if i == "(" then
    left << j+1
  else
    paren[left.pop] = j+1
  end
end
if s[k-1] == "(" then
  puts paren[k]
else
  puts paren.key(k)
end