#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n, k, top;
    string s;
    stack<int> st;
    vector<int> v(n);

    cin >> n >> k >> s;
    for (int i = 0; i < n; i++) {
        if (s[i] == '(') {
            st.push(i);
        } else {
            top = st.top();
            st.pop();
            v[i] = top;
            v[top] = i;
        }
    }

    cout << v[k-1]+1 << endl;
    return 0;
}