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A. Repeating Cipher

time limit per test

1 secondmemory limit per test

256 megabytesinput

standard inputoutput

standard outputPolycarp loves ciphers. He has invented his own cipher called repeating.

Repeating cipher is used for strings. To encrypt the string $$$s=s_{1}s_{2} \dots s_{m}$$$ ($$$1 \le m \le 10$$$), Polycarp uses the following algorithm:

- he writes down $$$s_1$$$ ones,
- he writes down $$$s_2$$$ twice,
- he writes down $$$s_3$$$ three times,
- ...
- he writes down $$$s_m$$$ $$$m$$$ times.

For example, if $$$s$$$="bab" the process is: "b" $$$\to$$$ "baa" $$$\to$$$ "baabbb". So the encrypted $$$s$$$="bab" is "baabbb".

Given string $$$t$$$ — the result of encryption of some string $$$s$$$. Your task is to decrypt it, i. e. find the string $$$s$$$.

Input

The first line contains integer $$$n$$$ ($$$1 \le n \le 55$$$) — the length of the encrypted string. The second line of the input contains $$$t$$$ — the result of encryption of some string $$$s$$$. It contains only lowercase Latin letters. The length of $$$t$$$ is exactly $$$n$$$.

It is guaranteed that the answer to the test exists.

Output

Print such string $$$s$$$ that after encryption it equals $$$t$$$.

Examples

Input

6 baabbb

Output

bab

Input

10 ooopppssss

Output

oops

Input

1 z

Output

z

Codeforces (c) Copyright 2010-2019 Mike Mirzayanov

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