Problem Description

Arrays in a programming language are defined as follows:

• The beginning and end of an array are marked with curly braces ($\texttt \{$ and $\texttt \}$), respectively.
• Inside each pair of braces, there are several (possibly $0$) comma-separated elements (there is no comma after the last element of each array).
• Each element can be either a word (a string consisting of lowercase letters) or another array.
• Some valid arrays are: $\texttt {\{\}}, \texttt{\{a,b,c\}}, \texttt{\{abc,znj,\{novi,niz\},pozz\}}$.

You need to apply the following formatting style to make the program look nicer:

• Start a new line whenever you encounter a word or a curly brace.
• A comma should be placed directly after an array element.
• Every time you encounter a $\texttt{\{}$, increase the indentation by $2$ spaces.
• Every time you encounter a $\texttt{\}}$, decrease the indentation by $2$ spaces.

Given an array, output it in the above formatting style.

Input Format

A string $S$ representing the given array.

Output Format

The array formatted in the required style.

{abc,ono,sto}

{
  abc,
  ono,
  sto
}

{}

{
}

{znakovi}

{
  znakovi
}

{a,b,{c,d},e,{}}

{
  a,
  b,
  {
    c,
    d
  },
  e,
  {
  }
}

Hint

Constraints

• For $50\%$ of the testdata, elements contain only words.
• For $100\%$ of the testdata, $1 \le |S| \le 1500$.

Hints and Notes

The checker is from the Testlib library, see the attachment.

Translated from COCI 2015-2016 #7 Task 1 Nizovi.

The score for this problem follows the original COCI settings, with a full score of $50$.

Translated by ChatGPT 5