using System;
using System.Collections.Generic;
using System.Linq;

namespace Yukicoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var line = Console.ReadLine().Split(' ');

            int N = int.Parse(line[0]);
            int K = int.Parse(line[1]) - 1;

            List<int> list = new List<int>();
            var kakko = Console.ReadLine()
                .Select(
                x => x == '(' ? 0 : 1
                );

            list.AddRange(kakko);
            while (true)
            {
                int lastKakko = 0;
                for (int i = 0; i < N; i++)
                {
                    if(list[i] == 0)
                    {
                        lastKakko = i;
                        continue;
                    }

                    if(list[i] == 1)
                    {
                        list[lastKakko] = -1;
                        list[i] = -1;

                        if(lastKakko == K)
                        {
                            Console.WriteLine(i + 1);
                            return;
                        }else if(i == K)
                        {
                            Console.WriteLine(lastKakko + 1);
                            return;
                        }
                        break;
                    }
                }
            }
            
        }

    }
}