#include <iostream>
#include <stack>
using namespace std;

int main() {
    int n, k;
    stack<int> st;
    string s;
    cin >> n >> k >> s;
    int cor[n];
    for (int i = 0; i < s.size(); i++) {
        if (s[i] == '(')
            st.push(i);
        else {
            int x = st.top();
            cor[x] = i;
            cor[i] = x;
            st.pop();
        }
    }
    cout << cor[k-1]+1 << endl;
    return 0;
}