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 OCaml (4.10.0) (judge verdict: Wrong Answer)

open Batteries
let n = read_int ()
let a = read_line () 
let a2 = a |> String.split_on_char ' ' |> List.map int_of_string
let rec loop lst r=
  match lst with
  | [] -> r
  | first :: rest ->
    if List.mem 0 a2 then 0 else
    if first = 0 then 0 else
    if first <> 1 && max_int / 2 <= r then -1 else
    loop rest (r*first)

let l = loop a2 1
let _ = (if l > 1000000000000000000 || l < 0 then -1 else l) |> Printf.printf "%d\n"