fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

fn main() {
  let input1: Vec<usize> = read_vec();
  let input2: String = read();
  let mut pairs: Vec<Option<usize>> = vec![None; input1[0]];

  use std::collections::VecDeque;
  let mut opend_at_queue = VecDeque::new();

  let chars = input2.chars().collect::<Vec<char>>();
  for i in 0..chars.len() {
    if chars[i] == '(' {
      opend_at_queue.push_back(i)
    } else {
      let opend_at = opend_at_queue.pop_back().unwrap();
      pairs[opend_at] = Some(i);
      pairs[i] = Some(opend_at);
    }
  }
  
  let ans = pairs[input1[1]-1].unwrap() + 1;
  println!("{}", ans)
}