Repeating Cipher

1000ms

262144K

Description:

Polycarp 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 $$$t$$$.

Sample Input:

6
baabbb

Sample Output:

bab

Sample Input:

10
ooopppssss

Sample Output:

oops

Sample Input:

1
z

Sample Output:

Informação

Provedor Codeforces

Código CF1095A