Product of Nonzero Values

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Multiply all nonzero values among n integers. If there is no nonzero value, output 0, including n=0.

Input

n in [0,20], followed by n integers in [-5,5].

Output

The 64-bit product, or 0 if no nonzero element exists.

Subtasks

• Subtask 1 (20%): $n\le3$, $|a_i|\le2$.
• Subtask 2 (30%): $n\le10$, $|a_i|\le3$.
• Subtask 3 (50%): $n\le20$, $|a_i|\le5$.

Examples

Example 1

Input

5
0 -2 0 3 1

Output

-6

Explanation

Ignore zeros and multiply (-2)31=-6.

Example 2

Input

3
0 0 0

Output

0

Explanation

No nonzero factor exists, so output 0.