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

using namespace std;

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

  long long l = 0;
  long long r = 0;

  vector<pair<long long, long long>> lr;
  long long ans = 0;
  long long C = 0;
  for (int i = 0; i < n; i++) {
    if (s[i] == '(') {
      r++;
    } else {
      if (r > 0) {
        r--;
        C++;
      } else {
        l++;
      }
    }
    lr.emplace_back(l, r);
    ans += C * 2;
  }
  sort(lr.begin(), lr.end(), [](auto a, auto b) { return min(-a.first, -a.first + a.second - b.first) > min(-b.first, -b.first + b.second - a.first); });
  r = 0;
  for (auto p : lr) {
    long long take = min(r, p.first);
    r -= take;
    ans += take * 2;
    r += p.second;
  }
  cout << ans << endl;
}