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

int main()
{
    int N, K;
    string S;
    cin >> N >> K >> S;
    vector<int> list;
    vector<int> ans(N);
    for (int i = 0; i < N; i++)
    {
        if (S[i] == '(')
        {
            list.push_back(i);
        }
        if (S[i] == ')')
        {
            int tmp = list.back();
            ans[tmp] = i;
            ans[i] = tmp;
            list.pop_back();
        }
    }
    cout << ans[K - 1] + 1;
}