#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
int main() {
    // Input
    int N, K;
    cin >> N >> K;
    string S;
    cin >> S;

    // Simulation And Output
    --K;
    deque<pair<char, int>> p;
    rep(i, S.size()) {
        if (S[i] == '(') {
            p.push_back({S[i], i});
        } else {
            int j = p.back().second;
            p.pop_back();
            if (i == K) cout << j + 1 << endl;
            if (j == K) cout << i + 1 << endl;
        }
    }
}