using System;
using System.Collections.Generic;
using System.Text;
class Program
{
    public void Proc()
    {
        Reader.IsDebug = false;
        int[] intArray = Reader.GetInt();
        int textLen = intArray[0];
        int target = intArray[1];

        string inpt = Reader.ReadLine();
        Stack<PartOfText> stk = new Stack<PartOfText>();
        for (int i = 0; i < inpt.Length; i++)
        {
            PartOfText pt = new PartOfText();
            pt.Pos = i + 1;
            pt.CharOfText = inpt[i];
            if (pt.CharOfText == '(')
            {
                stk.Push(pt);
            }
            else
            {
                PartOfText pair = stk.Pop();
                if (pt.Pos == target)
                {
                    Console.WriteLine(pair.Pos);
                    return;
                }
                else if (pair.Pos == target)
                {
                    Console.WriteLine(pt.Pos);
                    return;
                }

            }
        }


    }


    public class PartOfText
    {
        public char CharOfText;
        public int Pos = 0;
    }

    


    public class Reader
    {
        public static bool IsDebug = true;
        private static String PlainInput = @"
 


20 5
((((((()))))))(()())



 
";
        private static System.IO.StringReader Sr = null;
        public static string ReadLine()
        {
            if (IsDebug)
            {
                if (Sr == null)
                {
                    Sr = new System.IO.StringReader(PlainInput.Trim());
                }
                return Sr.ReadLine();
            }
            else
            {
                return Console.ReadLine();
            }
        }
        public static int[] GetInt(char delimiter = ' ', bool trim = false)
        {
            string inptStr = ReadLine();
            if (trim)
            {
                inptStr = inptStr.Trim();
            }
            string[] inpt = inptStr.Split(delimiter);
            int[] ret = new int[inpt.Length];
            for (int i = 0; i < inpt.Length; i++)
            {
                ret[i] = int.Parse(inpt[i]);
            }
            return ret;
        }
    }
    static void Main()
    {
        Program prg = new Program();
        prg.Proc();
    }
}