#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pii pair<int, int>
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep3(i, l, n) for (int i = l; i < (n); ++i)
#define sz(v) (int)v.size()
#define endl '\n'
const int inf = 1000000007;
const ll INF = 1e18;
int mod = 998244353;
// int mod = 1000000007;
#define abs(x) (x >= 0 ? x : -(x))
#define lb(v, x) (int)(lower_bound(all(v), x) - v.begin())
#define ub(v, x) (int)(upper_bound(all(v), x) - v.begin())
template<typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { if (a > b) { a = b; return 1; } return 0; }
template<typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { if (a < b) { a = b; return 1; } return 0; }
ll gcd(ll a, ll b) { if (b == 0) return a; return gcd(b, a % b); }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
template<typename T, typename U> T pow_(T a, U b) { return b ? pow_(a * a, b / 2) * (b % 2 ? a : 1) : 1; }
ll modpow(ll a, ll b, ll _mod) { return b ? modpow(a * a % _mod, b / 2, _mod) * (b % 2 ? a : 1) % _mod : 1; }
template<class T, class U> ostream& operator << (ostream& os, const pair<T, U>& p) { os << p.F << " " << p.S; return os; }
template<class T> ostream& operator << (ostream& os, const vector<T>& vec) { rep(i, sz(vec)) { if (i) os << " "; os << vec[i]; } return os; }
template<typename T> inline istream& operator >> (istream& is, vector<T>& v) { rep(j, sz(v)) is >> v[j]; return is; }
template<class T, class T2> inline void add(T &a, T2 b) { a += b; if (a >= mod) a -= mod; }


void solve();

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cout << fixed << setprecision(10);
  int T;
  T = 1;
  while (T--) solve();
}

// https://atcoder.jp/contests/abc167/tasks/abc167_f
void solve() {
  int n;
  cin >> n;
  vector<string> s(n);
  string w;
  cin >> w;
  string u;
  rep(i, n) {
    u += w[i];
    s[i] = u;
  }

  using t = tuple<int, int, int>;
  vector<t> v;

  // 最下点と, 始点終点の高さの変化
  auto calc = [&](string s) {
    int now = 0, mi = 0;
    rep(j, sz(s)) {
      if (s[j] == ')') {
        now--;
        chmin(mi, now);
      } else {
        now++;
      }
    }
    return pii(mi, now);
  };

  rep(i, n) {
    int now = 0, mi = 0;
    pii tmp = calc(s[i]);
    if (tmp.S >= 0) v.eb(tmp.F, tmp.S, i);
  }

  auto comp = [&](t a, t b) { // debuged, 最下点だけ
    int mi1 = get<0>(a), now1 = get<1>(a);
    int mi2 = get<0>(b), now2 = get<1>(b);
    return mi1 > mi2; // 最下点が大きい順
  };

  auto out = [&](vector<t> v) {
    rep(i, n) {
      int mi, now, j;
      tie(mi, now, j) = v[i];
      cout << mi << " " << now << " " << j << endl;
    }
  };

  sort(all(v), comp);
  reverse(all(v)); // 後ろから pop していく

  string ans;
  for (int i = sz(v) - 1; i >= 0; --i) {
    ans += s[get<2>(v[i])];
  }

  v.clear();
  rep(i, n) {
    int now = 0, mi = 0;
    pii tmp = calc(s[i]);
    if (tmp.S < 0) v.eb(tmp.F, tmp.S, i);
  }

  auto calc2 = [&](string s) {
    int now = 0, mi = 0;
    for (int j = sz(s) - 1; j >= 0; --j) {
      if (s[j] == '(') { // debuged
        now--;
        chmin(mi, now);
      } else {
        now++;
      }
    }
    return pii(mi, now);
  };

  rep(i, sz(v)) {
    // debuged, removed t
    pii tmp = calc2(s[get<2>(v[i])]);
    // cout << tmp << endl;
    v[i] = make_tuple(tmp.F, tmp.S, get<2>(v[i]));
  }

  sort(all(v), comp);
  // debuged, removed, reverse
  for (int i = sz(v) - 1; i >= 0; --i) ans += s[get<2>(v[i])];

  {
    int now = 0, cnt = 0;
    rep(i, sz(ans)) {
      if (ans[i] == ')') {
        if (now >= 1) {
          now--;
          cnt++;
        }
      } else {
        now++;
      }
    }
    cout << cnt * 2 << endl;
  }
}