Problem Statement

$N$ cards, each with an integer from $-9 \ $ to $ \ 9$ written on it, are lined up in a row.
You want to form an expression by placing $1$ card with one of $+,-,×,÷$ written on it between each pair of adjacent integer cards. $($There are infinitely many cards of each kind.$)$
The operators have no precedence; the expression is evaluated from left to right.
Find the maximum possible value of the resulting expression.

[Handling of $÷$]
・Division by 0 is not allowed, so it must not be placed before a 0.
・If the division is not exact, the fractional part is truncated toward 0 $($ignored$)$.

Input

$N$
$a_1 \ a_2 \ ... \ a_N$

The $1$st line contains $N$.
The $2$nd line contains the integers written on the cards, separated by spaces.

$2 \le N \le 16$
$-9 \le a_i \le 9$

Output

Output the maximum value.

Sample

4
0 -9 1 5

50

8
6 6 1 3 3 2 2 -1

1333

16
6 9 1 2 1 2 1 2 1 4 1 4 1 8 1 2

114514