import java.util.*;
import java.math.*;
import java.io.*;
 
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int k = sc.nextInt()-1;
		char[] s = sc.next().toCharArray();
		while(true)
		for(int i = 0; i < n; i++) {
			if(s[i] == ')' || s[i] == ' ') continue;
			if(s[i] == '(') {
				for(int j = i + 1; j < n; j++) {
					if(s[j] == ' ') continue;
					if(s[j] == '(') break;
					if(s[j] == ')') {
						if(i == k) {
							System.out.println(j+1);
							return;
						}
						else if(j == k) {
							System.out.println(i+1);
							return;
						}
						else {
							s[i] = ' ';
							s[j] = ' ';
							break;
						}
					}
				}
			}
		}
	}
}