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

namespace YukiCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var va = Console.ReadLine().Split().Select(int.Parse).ToArray();
            var sa = Console.ReadLine();
            var sk = new Stack<int>();
            var pa = new int[va[0]];
            for (int i = 0; i < va[0]; i++)
            {
                if (sa[i] == '(') sk.Push(i);
                else
                {
                    int j = sk.Pop();
                    pa[i] = j;
                    pa[j] = i;
                }
            }
            Console.WriteLine(pa[va[1] - 1] + 1);
            Console.ReadLine();
        }
    }
}