Problem:
Score : 200 points

Problem Statement

Given N integers A_1, ..., A_N, compute A_1 \times ... \times A_N.

However, if the result exceeds 10^{18}, print -1 instead.

Constraints

2 \leq N \leq 10^5

0 \leq A_i \leq 10^{18}

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 ... A_N

Output

Print the value A_1 \times ... \times A_N as an integer, or -1 if the value exceeds 10^{18}.

Sample Input 1

2
1000000000 1000000000

Sample Output 1

1000000000000000000

We have 1000000000 \times 1000000000 = 1000000000000000000.

Sample Input 2

3
101 9901 999999000001

Sample Output 2

-1

We have 101 \times 9901 \times 999999000001 = 1000000000000000001, which exceeds 10^{18}, so we should print -1 instead.

Sample Input 3

31
4 1 5 9 2 6 5 3 5 8 9 7 9 3 2 3 8 4 6 2 6 4 3 3 8 3 2 7 9 5 0

Sample Output 3

0

Solution in C# (Mono-mcs 6.8.0.105) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        var input = Console.ReadLine();
        var inputs = Console.ReadLine().Split(' ');
        ulong ans = 1;
        var flag = true;

        foreach (var n in inputs)
        {
            if (flag)
            {
                if (n.ToCharArray().Length + ans.ToString().ToCharArray().Length > 21)
                {
                    ans = 1000000000000000001;
                    flag = false;
                }
                else 
                {
                    ans *= ulong.Parse(n);

                    if (ans > (ulong)Math.Pow(10, 18))
                    {
                        flag = false;
                    } 
                }
            }
            else
            {
                if (long.Parse(n) == 0)
                {
                    ans = 0;
                }
            }
        }
        if (ans > (ulong)Math.Pow(10, 18))
        {
            Console.WriteLine(-1);
        }
        else
        {
            Console.WriteLine(ans);
        }
        Console.Read();
    }
}