The story, background information, and an outline of problem goes here.

Thanks to [user:quantum], [user:Xyene] and [user:FatalEagle] for supporting users mentions from [user:SourSpinach] to [user:grikukan] to [user:jimgao] to [user:cheesecake] to [user:NoWoDeYo] to [user:Zhenpai] to [user:global_smurf].

Inline math: ~(0 \le N \le 10^9)~

Display math:
$$f(x) = \begin{cases} 1 & \text{if } x\in\mathbb{Q} \\\\ -1 & \text{if } x\not\in\mathbb{Q} \end{cases}$$

Real ~\LaTeX~ ([use this for diagrams](https://dmoj.ca/problem/ds4)):
<latex>
\documentclass{standalone}
\begin{document}
\huge $E=mc^2$
\end{document}
</latex>

Complexity notation (rarely used for problems): ~\mathcal{O}(N^3 \log K)\ \forall\ N, K \in \mathbb{Z}^{+}~

You can make ~\LaTeX~ treat a word like an operator. Compare ~X \operatorname{word} Y~ with ~X \log Y~.

Mod chart! Refer to this if you're confused about mod.

<table class="table" style="max-width:60%">
<tr>
 <th>Command</th>
 <th>Example</th>
 <th>Comment</th>
</tr>
<tr>
 <td>`\mod`</td>
 <td>~1 \mod 2~</td>
 <td>Should be rarely used.</td>
</tr>
<tr>
 <td>`\bmod`</td>
 <td>~1 \bmod 2~</td>
 <td>Should be commonly used.</td>
</tr>
<tr>
 <td>`\pmod`</td>
 <td>~1 \pmod 2~</td>
 <td>Should be used normally.</td>
</tr>
<tr>
 <td>`\text{ mod }`</td>
 <td>~1 \text{ mod } 2~</td>
 <td>Bulky, should be used as a last resort.<br>Looks identical to `\bmod` in this case.</td>
</tr>
</table>

***bold and italic***, **bold**, *italic*

> Block-quote text

 1. An ordered list item
 2. Another ordered list item

* Unordered list item
   * Nested list item

[Links][1] for interesting references are sometimes used.

![Images are fun too][2]

Code can be syntax-highlighted:

```c++
#include <cstdio>

int main()
{
    puts("Here is a code snippet in C++.");
    return 0;
}
```

You can use HTML and CSS styles:
<div style="width: 90px; height: 90px; background: red; color: white; font-weight: bold; text-align: center; padding: 5px">this is a box<br/>it is red</div>

Keep your problem statements professional, and do not abuse this!

## Input Specification

A description of the input format goes here.

The first line of the input will contain an integer ~N~, representing the number of elements in array ~A~.

The next ~N~ lines will each contain an element ~a_i~ ~(1 \le i \le N)~, denoting the elements of array ~A~.

## Constraints

A description of the bounds of all defined variables goes here.

**Note:** This is optional, and usually reserved for problems with subtasks.

For all subtasks:

~1 \le a_i \le 100~

### Subtask 1 [20%]

~1 \le N \le 20~

### Subtask 2 [30%]

~1 \le N \le 1\,000~

### Subtask 3 [50%]

~1 \le N \le 10^5~

Alternatively, you may use a table to communicate details in bulk:

<table class="table" style="max-width:50%">
<thead>
<tr>
  <th>Subtask</th>
  <th>Marks</th>
  <th>~N~</th>
</tr>
</thead>
<tbody>
<tr>
  <td>~1~</td>
  <td>~20\%~</td>
  <td>~1 \le N \le 20~</td>
</tr>
<tr>
  <td>~2~</td>
  <td>~30\%~</td>
  <td>~1 \le N \le 1\,000~</td>
</tr>
<tr>
  <td>~3~</td>
  <td>~50\%~</td>
  <td>~1 \le N \le 10^{5}~</td>
</tr>
</tbody>
</table>

## Output Specification

A description of what the user's program should output goes here.

Output the sum of all of the prime numbers in array ~A~.

## Sample Input
    5
    1 2 3 4 5

## Sample Output
    10

## Explanation

Optional: an explanation of how the Sample Output was produced goes here, clarifying details for the user.

A prime number has exactly two divisors: ~1~ and itself. The prime numbers in ~A~ are ~2, 3~ and ~5~, so the output is ~2 + 3 + 5 = 10~.

  [1]: https://google.ca
  [2]: https://www.google.ca/doodle4google/images/splashes/featured.png