#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <iomanip>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
using namespace std;
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
#define LONGINF 1000000000000000000
int main() {
	int n, k;
	cin >> n >> k;
	string s;
	cin >> s;
	stack<int> hoge;
	REP(i, s.length()) {
		if (s[i] == '(') {
			hoge.push(i + 1);
		}else if(s[i] == ')'){
			int tmp = hoge.top();
			hoge.pop();
			if (i + 1 == k) {
				cout << tmp << endl;
				return 0;
			}
			if (tmp == k) {
				cout << i + 1 << endl;
				return 0;
			}
		}
	}
}