#include <bits/stdc++.h>
using namespace std;
int main() {
	int N, K;
	cin >> N >> K;
	string S;
	cin >> S;
	int a[10000];
	stack<int> s;
	for(int i = 0; i < S.length(); i++) {
		if(S[i] == '(') {
			s.push(i);
		}
		else {
			int x = s.top();
			a[i] = x;
			a[x] = i;
			s.pop();
		}
	}
	cout << (a[K - 1] + 1) << endl;
	return 0;
}