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Statement

Polycarp loves ciphers. He has invented his own cipher called Right-Left.

Right-Left cipher is used for strings. To encrypt the string s=s1s2sn s=s_{1}s_{2} \dots s_{n} Polycarp uses the following algorithm:

  • he writes down s1 s_1 ,
  • he appends the current word with s2 s_2 (i.e. writes down s2 s_2 to the right of the current result),
  • he prepends the current word with s3 s_3 (i.e. writes down s3 s_3 to the left of the current result),
  • he appends the current word with s4 s_4 (i.e. writes down s4 s_4 to the right of the current result),
  • he prepends the current word with s5 s_5 (i.e. writes down s5 s_5 to the left of the current result),
  • and so on for each position until the end of s s .

For example, if s s ="techno" the process is: "t" \to "te" \to "cte" \to "cteh" \to "ncteh" \to "ncteho". So the encrypted s s ="techno" is "ncteho".

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

Format

Input

The only line of the input contains t t — the result of encryption of some string s s . It contains only lowercase Latin letters. The length of t t is between 1 1 and 50 50 , inclusive.

Output

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

Sample

ncteho
techno
erfdcoeocs
codeforces
z
z

ShanghaiTech ACM 炸鱼杯

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开始于
2024-12-10 23:00
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2024-12-15 13:00
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