import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
import java.math.*;
 
public class Main {
	public static void main(String[] args)throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		String[] str = br.readLine().split(" ");
		int n = Integer.parseInt(str[0]);
		int k = Integer.parseInt(str[1]);
		String a = br.readLine();
		int[] f = new int[n/2];
		int[] l = new int[n/2];
		int cnt = 0;
		int pos = -1;
		for(int i = 0; i < n; i++){
			char c = a.charAt(i);
			if(c=='('){
				f[cnt]=i+1;
				if(i+1==k)pos = cnt;
				cnt++;
			}else{
				cnt--;
				l[cnt]=i+1;
				if(i+1==k){
					sb.append(f[cnt]);
					System.out.println(sb);
					return;
				}
				if(pos==cnt){
					sb.append(l[cnt]);
					System.out.println(sb);
					return;
				}
			}
		}
	}
}