#include <iostream>
#include <vector>
#include <queue>

using namespace std;

enum class CH {
    open, close, plus, one, mul
};

char pop(queue<char> &q) {
    auto x = q.front();
    q.pop();
    return x;
}

int eval (queue<char> &q) {
    int res = 1;
    auto c = pop(q);
    while (true) {
        switch (c) {
            case '1':
                q.pop();
                //cout << "Ret 1"<<endl;
                return 1;
            default: // TODO '('
                res *= eval(q);
        }
        c = pop(q);
        switch (c) {
            case '*':
                q.pop();
                continue;
            default: // TODO "+1"
                q.pop();
                q.pop();
                //cout << "Ret res+1: "<< res + 1<<endl;
                return res + 1;
        }
    }
}

int ev(vector<char> &v) {
    queue<char> q;
    for (const auto x : v) {
        q.push(x);
    }
    q.pop();
    return eval(q);
}

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

    vector<char> v;

    for (int i = 0; i < n; i++) {
        char c;
        cin >> c;

        if (c == '(') {
            if (!v.empty() && v.back() == ')') {
                v.push_back('*');
            }
        } else { // TODO ')'
            if (v.back() == '(') {
                v.push_back('1');
            } else {
                v.push_back('+');
                v.push_back('1');
            }
        }
        v.push_back(c);
    }

    //for (const auto x : v) {
    //    cout << x << ' ';
    //}cout <<endl;
    cout /*<< "Res: "*/ << ev(v) << endl;

    return 0;
}