#include <bits/stdc++.h>
using namespace std;
#define rep(i , a, b) for(int i = a; i < (b) ; ++i)
#define all(x) std::begin(x), std::end(x)
#define sz(x) ((int) x.size())
typedef long long ll;
#define int ll
typedef pair<int,int> pii;

typedef vector<int> vi;

const ll mod = 1'000'000'007;

ll modpow(ll b, ll e) {
    ll ans = 1;
    for(;e ; b = b*b%mod,e/=2) {
        if(e & 1) ans = ans * b % mod;
    }
    return ans;
}

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    int n;
    cin >> n;
    int res = 0;
    int cur_res = 0;
    int stack = 0;
    char lastOperation = '+';
    vector<char> symbols(n);
    for (int i = 0; i < n; ++i) {
        cin >> symbols[i];
    }
    rep(i, 0, n)  {
        if (symbols[i] == ')') {
            if (i + 1 < n && symbols[i+1] == '(') {
                lastOperation = '*';
            }
            stack--;
            cur_res++;
        }
        if (symbols[i] == '(') {
            stack ++;
        }
        if (!stack) {
            if (cur_res) {
                if (!res) {
                    res += cur_res;
                }
                else {
                    if (lastOperation == '+') {
                        res += cur_res;
                    }
                    if (lastOperation == '*') {
                        res *= cur_res;

                        lastOperation = '+';
                    }
                }
                cur_res = 0;
            }
        }
    }
    if (cur_res) {
        if (lastOperation == '+') {
            res += cur_res;
        }
        if (lastOperation == '*') {
            res *= cur_res;
        }
    }
    cout << res << '\n';
    return 0;
}