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: Accepted)

let split_string ?(pattern="") = Str.split @@ Str.regexp pattern
let n = Scanf.sscanf (read_line ()) "%d" @@ fun n -> n
let ax = read_line () |> split_string ~pattern:" " |> List.map int_of_string

let i = int_of_float 1e18

let rec mul ans = function
  | [] -> Printf.printf "%d\n" @@ if ans > i then (-1) else ans
  | x :: xs -> 
      if x = 0 then print_endline "0"
      else if int_of_float (float i /. float ans) < x then print_endline "-1"
      else mul (ans * x) xs

let () = 
  if List.mem 0 ax then print_endline "0"
  else mul 1 ax