#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e6;
const long long MAX = 1e6 + 10;
const long long inf = 1e18 + 7;
long long a[MAX];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long n, ans = 0;
  cin >> n;
  if (n & 1) {
    cout << "0\n";
    return 0;
  }
  string s;
  cin >> s;
  for (long long i = 0; i < n; i++) {
    if (i) a[i] = a[i - 1];
    if (s[i] == '(')
      a[i]++;
    else
      a[i]--;
    if (a[i] < -2) {
      cout << "0\n";
      return 0;
    }
  }
  if (a[n - 1] != 2 && a[n - 1] != -2) {
    cout << "0\n";
    return 0;
  }
  if (a[n - 1] == 2) {
    for (long long i = 0; i < n; i++) {
      if (a[i] < 0) {
        cout << "0\n";
        return 0;
      }
    }
    for (long long i = n - 1; i >= 0; i--) {
      if (a[i] < 2) break;
      if (s[i] == '(') ans++;
    }
  }
  if (a[n - 1] == -2) {
    for (long long i = 0; i < n; i++) {
      if (i) {
        if (a[i - 1] < 0) break;
      }
      if (s[i] == ')') ans++;
    }
  }
  cout << ans << "\n";
  return 0;
}
