#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
#include <queue>
#include <numeric>
#include <cmath>
#include <iomanip>
#define int long long
#define ff first
#define ss second
using namespace std;
int opt(vector<int>& a, int x) {
priority_queue<int> pq;
int temp;
for(auto i : a) pq.push(i);
while(x--) {
temp = pq.top();
pq.pop();
pq.push(temp - 1);
}
int res = 1;
while(pq.size()) {
res *= pq.top();
pq.pop();
}
return res;
}
void dfs(vector<pair<bool,vector<int>>>& graph, string& s, int i, int l, int r) {
int last = l, cnt = 0;
for(int j = l; j <= r; j++) {
if(s[j] == '(') cnt++;
else if(s[j] == ')') {
cnt--;
if(!cnt) {
if(j != r) {
if(s[j + 1] == '*') graph[i].ff = true;
}
graph[i].ss.push_back(graph.size());
graph.push_back({false,{}});
dfs(graph, s, graph.size() - 1, last + 1, j - 1);
last = j + 2;
}
}
}
}
double dfss(vector<pair<bool,vector<int>>>& graph, vector<int>& a, int i) {
if(!graph[i].ss.size()) return a[0];
double res = (graph[i].ff ? 1 : 0), suum = 0, temp;
vector<int> kak;
for(auto j : graph[i].ss) {
temp = dfss(graph, a, j);
kak.push_back(temp);
if(graph[i].ff) res *= temp;
else res += temp;
suum += temp;
}
if(suum > a[graph[i].ss.size()-1]) {
if(graph[i].ff) {
return opt(kak, suum - a[graph[i].ss.size()-1]);
} else return a[graph[i].ss.size()-1];
}
return res;
}
void solve() {
int n;
cin >> n;
vector<int> a(n);
for(int i = 0; i < n; i++) cin >> a[i];
string s;
cin >> s;
vector<pair<bool,vector<int>>> graph(1, {false, {}});
dfs(graph, s, 0, 1, s.size() - 2);
cout << fixed << setprecision(5) << dfss(graph, a, 0) << "\n";
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
solve();
}
