import java.util.ArrayList;
import java.util.Scanner;

public class Main {	
	public static void main(String[] args) {
		try (Scanner scan = new Scanner(System.in)) {
			int N = scan.nextInt();
			int K = scan.nextInt();
			String S = scan.next();
			ArrayList<Node> list = new ArrayList<>();
			
			for(int j=0; j<S.length(); j++) {
				if(S.charAt(j) == '(') {
					int count = 0;
					for(int i=j; i<S.length(); i++) {
						if(S.charAt(i) == '(') {
							count++;
						} else if(S.charAt(i) == ')') {
							count--;
							if(count == 0) {
								list.add(new Node(j+1, i+1));
								break;
							}
						}
					}
				}
			}
			
			for(Node now : list) {
				if(now.first == K) {
					System.out.println(now.end);
					break;
				} else if(now.end == K) {
					System.out.println(now.first);
					break;
				}
			}
		}
	}
}

class Node {
	int first, end;
	Node(int f, int e) {
		first = f;
		end = e;
	}
}