#include <bits/stdc++.h>

using namespace std;

int main() {
    int n, k;
    string s;
    cin >> n >> k >> s;

    stack<int> st;
    vector<int> vt(n);
    for (int i = 0; i <n ; ++i) {
        if (s[i] == '(') {
            st.push(i);
        } else {
            int curt = st.top();
            st.pop();
            vt[i] = curt;
            vt[curt] = i;
        }
    }

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