#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 10;
int awsl[maxn];
int main() {
  int n;
  scanf("%d", &n);
  string s;
  cin >> s;
  vector<int> sum(n);
  vector<int> m(n);
  for (int i = 0; i < n; ++i) {
    if (s[i] == '(')
      awsl[i] = 1;
    else
      awsl[i] = -1;
  }
  sum[0] = awsl[0];
  for (int i = 1; i < n; ++i) {
    sum[i] = sum[i - 1] + awsl[i];
  }
  m.back() = sum.back();
  for (int i = n - 2; i >= 0; i--) {
    m[i] = min(sum[i], m[i + 1]);
  }
  int cnt = 0;
  for (int i = 0; i < n; ++i) {
    int v = 2 * awsl[i];
    if (m[i] - v >= 0 && sum.back() - v == 0) cnt++;
    if (sum[i] < 0) break;
  }
  cout << cnt << '\n';
}
