/**
 *    author:  otera    
**/
#include<iostream>
#include<string>
#include<cstdio>
#include<cstring>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<deque>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
using namespace std;

//#define int long long
typedef long long ll;
typedef unsigned long long ul;
typedef unsigned int ui;
typedef long double ld;
const int inf=1e9+7;
const ll INF=1LL<<60 ;
const ll mod=1e9+7 ;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef complex<ld> Point;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<int, int> P;
typedef pair<ld, ld> LDP;
typedef pair<ll, ll> LP;
#define fr first
#define sc second
#define all(c) c.begin(),c.end()
#define pb push_back
#define debug(x)  cerr << #x << " = " << (x) << endl;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

void solve() {
    int n;
	while(cin >> n) {
        if(n == 0) break;
        stack<P> st;
        if(n == 1) {
            int num; cin >> num;
            cout << num << endl;
            continue;
        }
        rep(i, n) {
            string t; cin >> t;
            int sz = (int)t.size();
            while(st.size() >= sz) {
                P p = st.top(); st.pop();
                P q = st.top(); st.pop();
                if(q.fr == 1) {
                    q.sc += p.sc;
                    st.push(q);
                } else {
                    q.sc *= p.sc;
                    st.push(q);
                }
            }
            if(t[sz - 1] == '+') {
                st.push(make_pair(1, 0));
            } else if(t[sz - 1] == '*') {
                st.push(make_pair(2, 1));
            } else {
                int num = t[sz - 1] - '0';
                // while(st.size() >= sz) {
                //     P p = st.top(); st.pop();
                //     P q = st.top(); st.pop();
                //     if(q.fr == 1) {
                //         q.sc += p.sc;
                //         st.push(q);
                //     } else {
                //         q.sc *= p.sc;
                //         st.push(q);
                //     }
                // }
                P q = st.top(); st.pop();
                if(q.fr == 1) {
                    q.sc += num;
                    st.push(q);
                } else {
                    q.sc *= num;
                    st.push(q);
                }
            }
        }

        while(st.size() >= 2) {
            P p = st.top(); st.pop();
            P q = st.top(); st.pop();
            if(q.fr == 1) {
                q.sc += p.sc;
                st.push(q);
            } else {
                q.sc *= p.sc;
                st.push(q);
            }
        }

        cout << st.top().sc << endl;
    }
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(10);
	//int t; cin >> t; rep(i, t)solve();
	solve();
    return 0;
}


Measured memory_bytes: 3192