## Goal

Finally, we have received the first messages from aliens! Unfortunately, we cannot understand them because they have a very unique way of speaking.

Here is how aliens encode their messages:

- At each step of the encoding, they remove a bigger part from the beginning of the original message, starting from 1 character only. First, they take the first character, then 2 characters, then 3, etc...

- Starting from an empty result string, they add each part taken from the original message alternatively at the end and at the beginning of the result string. They add the first part at the end, the second part at the beginning, the third part at the end, etc...

**Example**

abcdefgh becomes ghibcadef

1) Take "a" from abcdefghi, add it at the end of an empty string -> a

2) Take "bc" from bcdefghi, add it at the beginning of a -> bca

3) Take "def" from defghi, add it at the end of bad -> bcadef

4) Take the remaining characters "ghi" and add it at the beginning of bcadef -> ghibcadef

Your job here is to **decode** or **encode** the messages to discuss with aliens.
Input

**Line 1:** An integer `N` indicating the number of times the message was transformed. If `N` is **positive** you have to **decode** i.e. retrieve the original message. If `N` is **negative** you have to **encode** i.e. transform the message.

**Line 2:** A string `message` to be decoded or encoded.

Output

One line: The original message (if `N` is **positive**) or the transformed message (if `N` is **negative**).

Constraints

-10 ≤ `N` ≤ 10

0 < `message` length < 1024