# Transform Set of Strings to Common Prefix Notation

## Description

Presented with a series of lines on standard input, the program will
print an expression on standard output that denotes the line strings
in a syntax described in <https://tk-sls.de/wp/6071>.

The expression is suitable for Bourne Again Shell brace expansion.

## Test

```
$ python3 trie.py << EOF
a
ab
abc
EOF
```

Expected output:

```
a{,b{,c}}
```

Test if the output is accurate:

```
$ bash -c 'echo a{,b{,c}}'
```

Expected output:

```
a ab abc
```