#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;
    string s;
    cin >> s;

    int cnt_one = 0;

    vector<int> res;
    int prev = 0;

    for(int i = 1; i < s.length(); i++) {
        if(s[i-1] == '(' && s[i] == ')') {
            prev = prev*10 + 1;
        } else if(s[i-1] == ')' && s[i] == ')') {
            res.push_back(prev);
            prev = 1;
        } else if(s[i-1] == ')' && s[i] == '(') {
            res.push_back(prev);
            prev = 0;
        }
    }

    res.push_back(prev);

    int sum = 0;
    for(int i = 0; i < res.size(); i++) {
        sum += res[i];
    }

    cout << sum << endl;

    return 0;
}