#include <iostream>

using namespace std;
int main() {
    int n_letters, n_cookies=0;
    cin >> n_letters;
/*    char curr;
    for (int i = 0; i < n_letters; ++i) {
        cin >> curr;
        n_letters += (curr == ')');
    }*/

    char prev, curr;
    cin >> curr;
    for (int i = 1; i < n_letters; ++i) {
        prev = curr;
        cin >> curr;
//        n_cookies += ((prev == '(' && curr == ')') || (prev == ')' && curr == ')'));
        n_cookies += (prev == ')');
    }
    n_cookies += (curr == ')');
    cout << n_cookies << endl;
    return 0;
}