#include<iostream>
#include<stdio.h>
#include<string>
#include<vector>

using namespace std;

int main()
{
	int num;
	int aim;
	int i = 0;
	int tmp;
	char c;
	vector<int> start;
	vector<int> end;
	string s;
	cin >> num >> aim;
	cin >> s;

	while (num > i)
	{
		c = s[i];
		if (c == '(')
			start.push_back(i);
		if (c == ')')
			end.push_back(i);
		i++;
	}
	i = 0;
	while (1)
	{
		if (aim-1 == start[i])
		{
			cout << end[num / 2 - i];
			break;
		}
		if (aim-1 == end[i])
		{
			cout << start[num / 2 - i];
			break;
		}
		i++;
	}


	return 0;
}