#include <bits/stdc++.h>
using namespace std;

namespace
{
char S[ 10000 ];
}

int main()
{
int i;
int iL;
int N;
int K;
vector<int> V;

	cin >> N;
	cin >> K;
	cin >> S;

	K--;
	for( i = 0; i < N; i++ )
	{
		if( S[ i ] == '(' )
		{
			V.push_back( i );
			continue;
		}

		iL = V.back();
		V.pop_back();
		if( iL == K )	cout << i + 1 << endl;
		if( i == K )	cout << iL + 1 << endl;
	}

	return 0;
}