#include <vector>
#include <list>
#include <map>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <queue>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <fstream>
#include <cstdio>
#include <climits>
#include <complex>
#include <cstdint>
#include <tuple>

#define M_PI       3.14159265358979323846

using namespace std;

//conversion
//------------------------------------------
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; }
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); }
inline int readInt() { int x; scanf("%d", &x); return x; }

//typedef
//------------------------------------------
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<int, PII> TIII;
typedef long long LL;
typedef unsigned long long ULL;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;

//container util

//------------------------------------------
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define SQ(a) ((a)*(a))
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c) sort((c).begin(),(c).end())

//repetition
//------------------------------------------
#define FOR(i,s,n) for(int i=s;i<(int)n;++i)
#define REP(i,n) FOR(i,0,n)
#define MOD 1000000007

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()


struct Edge {
    int to, cost, nm;
    Edge(int to, int cost, int nm): to(to), cost(cost), nm(nm) {}
};

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vector<Edge>> AdjList;
AdjList graph;
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
const int INF = 100000000;

ll GCD(ll a, ll b){
    if(a < b) swap(a, b);
    if(b == 0) return a;
    return GCD(b, a%b);
}

bool cmp(const pii& a, const pii& b){
    if(a.first == b.first){
        return a.second < b.second;
    }
    return a.first < b.first;
}


int N, M;
int arr[100010];


int main() {

    int n;
    //cout << fixed << setprecision(2);

    while(cin >> n) {
        if (n == 0) break;

        stack<pair<char, int>> st;
        stack<pair<int, int>> st2;
        vector<pair<string, int>> v;
        int prev_len = -1;

        for(int i=0; i<n; ++i){
            string s; cin >> s;
            v.push_back(make_pair(s, (int)s.size()));
        }
        for (int i = 0; i < n; ++i) {
            string s = v[i].first;

            int len = s.size();
            char c = s[len-1];
            if(i){
                if(v[i].second < v[i-1].second){

                    while(1) {
                        char c2 = st.top().first;
                        int len2 = st.top().second;

                        if (len > len2) break;

                        st.pop();
                        int t = st2.top().first;
                        st2.pop();
                        while(st2.size() && st2.top().second == len2 + 1){
                            if(c2== '*'){
                                t = t * st2.top().first;
                            }else if( c2 == '+'){
                                t = t + st2.top().first;
                            }
                            st2.pop();
                        }

                        st2.push(make_pair(t, len2));
                    }

                }
            }

            if(c == '*' || c == '+'){
                st.push(make_pair(c, len));
            }else if(c >= '0' && c <= '9'){
                st2.push(make_pair(c-'0', len));
            }
        }

        while(st.size()){
            char c = st.top().first;
            int len = st.top().second;

            st.pop();
            int t = st2.top().first;
            st2.pop();
            while(st2.size()!=0 && st2.top().second == len+1){
                if(c == '*'){
                    t = t * st2.top().first;
                }else if(c == '+'){
                    t = t + st2.top().first;
                }
                st2.pop();
            }
            st2.push(make_pair(t, len));
        }

        cout << st2.top().first << endl;
    }
    return 0;
}


Measured memory_bytes: 3140