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

class Program
{
    static void Main(string[] args)
    {
        string[] x = Console.ReadLine().Split();
        string s = Console.ReadLine();

        int n = int.Parse(x[0]);
        int k = int.Parse(x[1]);
        List<int> lst = new List<int>();
        int[] ary = new int[n];

        for (int i = 0; i < n; i++)
        {
            if (s[i] == '(')
            {
                lst.Add(i);
            }
            else
            {
                ary[lst[lst.Count - 1]] = i;
                ary[i] = lst[lst.Count - 1];
                lst.RemoveAt(lst.Count - 1);
            }
        }

        Console.WriteLine(ary[k - 1] + 1);
        Console.Read();
    }
}