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

namespace yukicoder_no22
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            int[] L1 = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            int N = L1[0];
			int K = L1[1] - 1;
            char[] S = Console.ReadLine().ToCharArray();

            int[] X = new int[N];

            var stack = new Stack();

            for (int i = 0; i < N; i++)
            {
                if (S[i] == '(') {
                    stack.Push(i);
                    continue;
                }

                if (S[i] == ')')
				{
                    int index = (int)stack.Pop();
                    X[index] = i;
                    X[i] = index;
					continue;
				}
            }

			Console.WriteLine("{0}", X[K] + 1);
        }
    }
}