using System;
using System.Collections.Generic;
using System.Linq;
public class Program{
    public static void Main(){
        var line = Console.ReadLine().Split(' ');
        var N = int.Parse(line[0]);
        var k = int.Parse(line[1])-1;
        var s = Console.ReadLine();
        var n = new int[N];
        var j = 1;
        while(n.Any(value => value==0)){
            for(var i=0;i<N-j;i++){
                if(n[i]==0 && s[i]=='(' && n[i+j]==0 && s[i+j]==')'){
                    n[i] = i+j+1;
                    n[i+j] = i+1;
                }
            }
            j++;
        }
        Console.WriteLine(n[k]);
    }
}