#include <bits/stdc++.h>
using namespace ::std;
using ll = long long;
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  int pref[n];
  pref[0] = ((s[0] == ')') ? -1 : 1);
  for (int i = 1; i < n; i++) {
    pref[i] = ((s[i] == ')') ? -1 : 1);
    pref[i] += pref[i - 1];
  }
  int msuf[n];
  msuf[n - 1] = pref[n - 1];
  for (int i = n - 2; i >= 0; i--) {
    msuf[i] = min(msuf[i + 1], pref[i]);
  }
  int mprev = 0;
  int count = 0;
  for (int i = 0; i < n; i++) {
    if (mprev < 0) break;
    if (msuf[i] + ((s[i] == ')') ? 2 : -2) == 0 &&
        pref[n - 1] + ((s[i] == ')') ? 2 : -2) == 0) {
      count++;
    }
    mprev = min(mprev, pref[i]);
  }
  cout << count << "\n";
}
