import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Deque;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;

public class Main{
	public static void main(String[] args) {
		try (BufferedReader br = 
				new BufferedReader(new InputStreamReader(System.in))) {
	        String[] N = br.readLine().split(" ");
	        int cntString = Integer.parseInt(N[0]);
	        int index = Integer.parseInt(N[1]);
	        String[] str = br.readLine().split("");

	        Deque<Integer> deq = new LinkedList<>();
	        Map<Integer, Integer> map = new HashMap<>();
	        
	        for (int i = 0; i < cntString; i++) {
	        	if (str[i].equals("(")) {
	        		deq.addFirst(i);
	        	}
	        	else {
	        		int j = deq.removeFirst();
	        		map.put(i, j);
	        		map.put(j, i);
	        	}
	        }
	        
	        System.out.println(map.get(index - 1) + 1);
		} catch (IOException e) {
			e.printStackTrace();
		}
    }
}