#[macro_export]
macro_rules! setup {
    { mut $input:ident: SplitWhitespace $(,)? } => {
        use std::io::Read;
        let mut buf = String::new();
        std::io::stdin().read_to_string(&mut buf).unwrap();
        let mut $input = buf.split_whitespace();
    };
}

#[macro_export]
macro_rules! parse_next {
    ($str_iter:expr) => {
        $str_iter.next().unwrap().parse().unwrap()
    };
}

use std::collections::HashMap;

fn main() {
    setup! { mut input: SplitWhitespace };

    let n: usize = parse_next!(input);
    let k: usize = parse_next!(input);
    let s: String = parse_next!(input);

    let cs = s.chars().collect::<Vec<_>>();

    let mut corr = HashMap::new();
    while corr.len() != n {
        for i in 0..(n - 1) {
            if corr.get(&i).is_some() {
                continue;
            }
            if !(cs[i] == '(') {
                continue;
            }
            let mut matched = false;
            for j in (i + 1)..n {
                if corr.get(&j).is_some() {
                    continue;
                }
                if cs[j] == ')' {
                    matched = true;
                    corr.insert(i, j);
                    corr.insert(j, i);
                }
                break;
            }
            if !matched {
                continue;
            }
            break;
        }
    }

    let ans = *corr.get(&(k - 1)).unwrap() + 1;

    println!("{}", ans);
}