c.cpp

#define __GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;

#define rep(i, n) for(int i = 0; i < (int)(n); ++i)
#define pb push_back
#define ALL(a) begin(a), end(a)
#define mp make_pair
#define F first
#define S second
#define SZ(a) ((int)(a.size()))
typedef long long ll;
typedef pair<int, int> PI;

vector<string> ap;
int n;

int pos = 0;

ll rec(int dep){
  if(isdigit(ap[pos][dep])){
    int tcp  = pos;
    ++pos;
    return ap[tcp][dep] - '0';
  }

  char op = ap[pos][dep];
  ++pos;
  ++dep;
  ll ret = rec(dep);
  while(pos < SZ(ap) && dep < SZ(ap[pos])){
    int p = rec(dep);
    if(op == '+') ret += p;
    else ret *= p;
  }
  return ret;
}

void solve(){
  ap.resize(n);
  rep(i, n) cin >> ap[i];
  pos = 0;
  cout << rec(0) << endl;
}

int main(int argc, char *argv[])
{

  while(cin >> n && n) solve();

  return 0;
}