#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 5;
bool A[N], poss[N];
int L[N], R[N], LL[N], RR[N];
int main() {
  ios_base ::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, l = 0, r = 0;
  cin >> n;
  for (int i = 0; i < n; i++) {
    char c;
    cin >> c;
    if (c == '(')
      A[i] = 1, l++;
    else
      r++;
    L[i] = l, R[i] = r;
  }
  l = 0, r = 0;
  for (int i = n - 1; i >= 0; i--) {
    if (A[i])
      l++;
    else
      r++;
    LL[i] = l, RR[i] = r;
  }
  if (abs(l - r) != 2) return cout << 0, 0;
  bool flag = 0;
  for (int i = 0; i < n; i++) {
    poss[i] = flag;
    if (R[i] > L[i]) flag = 1;
  }
  flag = 0;
  for (int i = n - 1; i >= 0; i--) {
    poss[i] |= flag;
    if (LL[i] > RR[i]) flag = 1;
  }
  int ans = 0;
  for (int i = 0; i < n; i++) {
    if (poss[i]) continue;
    if (A[i] && l > r) ans++;
    if (!A[i] && r > l) ans++;
  }
  cout << ans;
}
