#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
 
using namespace std;
using namespace __gnu_pbds; 
 
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> 
  
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define SZ(x) ((ll)(x).size())
#define POW2(n) (1LL << (n))
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
#define ITR(it,c) for(__typeof(c.begin()) it=c.begin();it!=c.end();it++)
#define IITR(it,c) for(__typeof(c.rbegin()) it=c.rbegin();it!=c.rend();it++)
#define DEBUG(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl;
#define ll long long
#define TEST int __T; cin >> (__T); while( (__T)-- )
#define Read() freopen("input.txt","r",stdin)
#define Write() freopen("output.txt","w",stdout)
#define ll_MAX ((ll)(1e19))
#define ll_MIN ((ll)(-1e19)
#define PB push_back
#define MP make_pair
#define F first
#define S second
#define umax(x,y) x=max(x,y)
#define umin(x,y) x=min(x,y)
 
template<typename T> void ndarray(vector<T> &vec, int len) { vec.resize(len); }
template<typename T, typename... Args> void ndarray(vector<T> &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); }
template<typename T> bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template<typename T> bool mmin(T &m, const T q) { if (q < m) {m = q; return true;} else return false; }
template<typename T> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }
template<typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template<typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
 
///// This part below is only for debug, not used /////
template<typename T> ostream &operator<<(ostream &os, const vector<T> &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const deque<T> &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
 
ll MAX = 1000000000000000000;
 
signed main(){
    
    int N;
    cin >> N;
    
    vector<ll> vec(N);
    
    int flag = 0;
    int count = 0;
    
    FOR(i,0,N) {
        cin >> vec[i];
        if(vec[i] == 0)
            flag = 1;
            
        ll temp = vec[i];
 
        while(temp/10 > 0){
            count++;
            temp /= 10;
        }
    }
    
    if(flag){
        cout << 0 << endl;
        return 0;
    }
    
    if(count > 18){
        cout << -1 << endl;
        return 0;
    }
    
    ll ans = 1;
    
    FOR(i,0,N){
        
        if(vec[i] <= MAX/ans){
            ans *= vec[i];
        }else{
            ans = -1;
            break;
        }
        
    }
    
    cout << ans << endl;
    
    return 0;
}

Measured memory_bytes: 3948