#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <time.h>
#include <cstdlib>
#include <cmath>
#include <fstream>

int main(void) {

	//test用
	//std::ifstream in("test.txt");
	//std::cin.rdbuf(in.rdbuf());

	int N, K;
	std::cin >> N >> K;

	std::string S;
	std::cin >> S;

	std::vector<std::size_t> pair(N);


	while (S.find(")") <= N) {
		std::size_t temp1,temp2;
		temp1 = S.find(")");
		temp2 = S.rfind("(", temp1);
		pair[temp1] = temp2;
		pair[temp2] = temp1;
		S[temp1] = '0';
		S[temp2] = '0';
	}

	std::cout << pair[K-1] + 1 << std::endl;
}