#include <algorithm>
#include <iostream>
#include <map>
#include <numeric>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <cmath>
#include <stack>
using namespace std;

int main() {
	stack<int> s;
	int N,K;
	cin >> N >> K;
	string kakko;
	cin >> kakko;
	int corr[N];

	for (int i=0;i<N;i++){
		if (kakko[i] == '('){
			s.push(i);
		}else{
			int a = s.top();
			corr[a] = i;
			corr[i] = a;
			s.pop();
		}
	}
	cout << corr[K-1]+1 << endl;
	return 0;
}