#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int n, l, r, ans;
string s;

struct Node {
    int L, R;
};
vector<Node> nodes;

int main() {
    scanf("%d", &n);
    cin >> s;

    for (int i = 0, match = 0; i < s.size(); ++i) {
        if (s[i] == '(') {
            ++l;
        } else {
            if (l > 0) {
                ++match;
                --l;
            } else {
                ++r;
            }
        }
        ans += match * 2;
        nodes.push_back({ l, r });
    }

    sort(nodes.begin(), nodes.end(), [](Node n1, Node n2) {
        bool n1_type = n1.R <= n1.L, n2_type = n2.R <= n2.L;
        if (n1_type != n2_type) return n1_type;
        if (n1.R <= n1.L) return n1.R < n2.R;
        return n1.L > n2.L;
    });

    l = 0LL;
    for (auto node : nodes) {
        int match = min(l, node.R);
        l -= match;
        l += node.L;
        ans += match * 2;
    }
    printf("%d\n", ans);

    return 0;
}