#include<iostream>
#include<stdio.h>
#include<stdlib.h>
#include<algorithm>
#include<vector>
#include<string.h>
#include<math.h>
#include<map>
#include<iomanip>
#include<stack>
#include<queue>
#include<set>

using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;

//const ll mod = 1000000007;
const ll mod = 998244353;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(15);
	int n , k;
	cin >> n >> k;
	string s;
	cin >> s;
	vector<pair<char , int>> ss;
	for(int i = 0; i < n; i++){
		ss.push_back(make_pair(s[i] , i + 1));
	}
	vector<pair<char , int>> tt;
	int ans = 0;
	for(int i = 0; i < ss.size(); i++){
		tt.push_back(ss[i]);
		if(tt[tt.size() - 2].first == '(' && tt[tt.size() - 1].first == ')'){
			if(tt[tt.size() - 2].second == k){
				ans = tt[tt.size() - 1].second;
				break;
			}else if(tt[tt.size() - 1].second == k){
				ans = tt[tt.size() - 2].second;
				break;
			}else{
				tt.pop_back();
				tt.pop_back();
			}
		}
	}
	cout << ans << endl;
	return 0;
}