use std::io::*;
use std::str::FromStr;

#[allow(dead_code)]
fn get_line() -> String {
    let stdin = stdin();
    let mut line = String::new();
    stdin.lock().read_line(&mut line).expect("io error.");
    line.trim().to_string()
}

#[allow(dead_code)]
fn cast<T: FromStr>(s: &str) -> T {
    s.parse().ok().expect("parse error.")
}

#[allow(dead_code)]
fn get_word<T: FromStr>() -> T {
    cast(&get_line())
}

#[allow(dead_code)]
fn get_vec<T: FromStr>() -> Vec<T> {
    (&get_line()).split(' ').map(cast::<T>).collect()
}



/* ---------- ここまでテンプレ ---------- */


fn main() {
    let v: Vec<usize> = get_vec();
    let (n, k) = (v[0], v[1] - 1);
    let s: Vec<char> = get_line().chars().collect();

    let mut par = vec![0usize; n];
    let mut stack = Vec::<usize>::new();

    for i in 0..n {
        match s[i] {
            '(' => {stack.push(i);}
            ')' => {
                let j = stack.pop().unwrap();
                par[i] = j;
                par[j] = i;
            }
            _ => ()
        };
    }

    // println!("{:?}", par);
    println!("{}", par[k] + 1);
}