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 Go (1.14.1) (judge verdict: Wrong Answer)

package main

import "fmt"
import "strconv"

func main() {
        var n int
        fmt.Scan(&n)
        var ans = 1
        var upper = 1000000000000000000
        for i := 0; i < n; i++ {
                var tmp int
                fmt.Scan(&tmp)
                if tmp == 0 {
                        ans = 0
                        break
                }
                if ans == -1 {
                        continue
                }
                var a = strconv.Itoa(tmp)
                var b = strconv.Itoa(ans)
                if len(a)+len(b) > 18 {
                        ans = -1
                        continue
                }
                ans *= tmp
                if ans > upper {
                        ans = -1
                }

        }
        fmt.Print(ans)
}