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

class Program
{
    static void Main(string[] args)
    {
        int[] n = Console.ReadLine().Split(' ').Select(a => int.Parse(a)).ToArray();
        string s = Console.ReadLine();
        int ans = 0;
        List<int> before = new List<int>();
        List<int> after = new List<int>();

        for (int i = 0; i < s.Length; i++)
        {
            if (s[i].ToString() == "(")
            {
                before.Add(i + 1);
            }
            else
            {
                after.Add(i + 1);
            }
        }

        int m = 0;

        if (s[n[1] - 1].ToString() == ")")
        {
            m = after.IndexOf(n[1]);
            m = (before.Count - m) - 1;
            ans = before[m];
        }
        else
        {
            m = before.IndexOf(n[1]);
            m = (after.Count - m) - 1;
            ans = after[m];
        }

        Console.WriteLine(ans);
        Console.ReadLine();
    }
}