/*
 * author :Sadik Hassan
 *
*/
#include "bits/stdc++.h"
using namespace std;
using   ll =          long long;
#define nl            "\n"
#define pb            push_back
#define fi            first
#define se            second
#define PI            (acos(-1.0))
#define repp(i,a,n)   for(int i=a;i<n;i++)
#define rep(i,n)      for(int i=0;i<n;i++)
#define SZ(s)         s.size()
#define SRT(x,y)      sort(x,x+y)
#define REV(a,b)      reverse(a,a+b)
#define VSRT(x)       sort(x.begin(),x.end())
#define VREV(x)       reverse(x.begin(),x.end())
#define w(t)          int t;cin>>t;while(t--)
#define TSFL(s)       transform(s.begin(),s.end(),s.begin(),::toupper);
#define TSFH(s)       transform(s.begin(),s.end(),s.begin(),::tolower);
#define _SAD()        ios::sync_with_stdio(0),cin.tie(0), cout.tie(0),cout<<fixed<<setprecision(15);
typedef vector<int> vi;
typedef vector<ll> vii;
typedef set<int> si;
typedef set<ll> sii;
/*---------------------------------------------------------------------*/

const int N = 2e5+10;
const int INF = (int)1e9+5;
string multiply(string num1, string num2)
{
    int len1 = num1.size();
    int len2 = num2.size();
    if (len1 == 0 || len2 == 0)
    return "0";

    // will keep the result number in vector
    // in reverse order
    vector<int> result(len1 + len2, 0);

    // Below two indexes are used to find positions
    // in result.
    int i_n1 = 0;
    int i_n2 = 0;

    // Go from right to left in num1
    for (int i=len1-1; i>=0; i--)
    {
        int carry = 0;
        int n1 = num1[i] - '0';

        // To shift position to left after every
        // multiplication of a digit in num2
        i_n2 = 0;

        // Go from right to left in num2
        for (int j=len2-1; j>=0; j--)
        {
            // Take current digit of second number
            int n2 = num2[j] - '0';

            // Multiply with current digit of first number
            // and add result to previously stored result
            // at current position.
            int sum = n1*n2 + result[i_n1 + i_n2] + carry;

            // Carry for next iteration
            carry = sum/10;

            // Store result
            result[i_n1 + i_n2] = sum % 10;

            i_n2++;
        }

        // store carry in next cell
        if (carry > 0)
            result[i_n1 + i_n2] += carry;

        // To shift position to left after every
        // multiplication of a digit in num1.
        i_n1++;
    }

    // ignore '0's from the right
    int i = result.size() - 1;
    while (i>=0 && result[i] == 0)
    i--;

    // If all were '0's - means either both or
    // one of num1 or num2 were '0'
    if (i == -1)
    return "0";

    // generate the result string
    string s = "";

    while (i >= 0)
        s += std::to_string(result[i--]);

    return s;
}
int main()
{
    _SAD()
    int n;
    cin>>n;
    vector<string> a(n);
    string s="1000000000000000000",k,ss;
    bool gu=0;
    rep(i,n)
    {
        cin>>a[i];
        if(SZ(a[i])==1&&a[i]=="0")gu=1;
    }
    if(gu)cout<<0<<nl;
    else
    {
        k=a[0];
        for(int i=1;i<n;i++)
        {
            string pp=multiply(k,a[i]);
            if(pp>s&&SZ(pp)>=SZ(s))
            {
                cout<<-1<<nl;
                return 0;
            }
            k=pp;
        }
        cout<<k<<nl;
    }
    return 0;
}


Measured memory_bytes: 11124