#include <bits/stdc++.h>

using namespace std;

using ull = unsigned long long;
int main() {
    cin.sync_with_stdio(false);
    cin.tie(0);
    size_t N;
    cin >> N;

    int index = -1;

    vector<size_t> v(N/2 + 3,0);
    for (size_t i = 0; i < N; i++){
        char ch;
        cin >> ch;
        if (ch == '('){
            index++;
        } else { // )
            if (v[index] != 0) {
                v[index] = v[index] * (v[index + 1] + 1);
                v[index + 1] = 0;
            } else {
                v[index] = 1 + v[index + 1];
                v[index + 1] = 0;
            }
            index--;
        }
    }
    cout << v[0] << endl;

    return 0;
}