#include <iostream>
#include <queue>
#include <stack>
#define FOR(i,s,e) for(int i = (s);i <= (e);i++)
using namespace std;

int N,K;
string S;

int memo[10000];
int main()
{
	cin >> N >> K;
	cin >> S;

	stack<int> s;

	FOR(i,0,N - 1)
	{
		if(S[i] == '(')
		{
			s.push(i);
		}
		else
		{
			int x = s.top();
			s.pop();
			memo[x] = i;
			memo[i] = x;
		}
	}

	cout << memo[K - 1] + 1 << endl;
	return 0;
}