Unique Strings Extraction

You are given a list of strings. Your task is to extract unique strings from the list in a case-insensitive manner, while preserving the order of their first occurrence. In other words, a string is considered a duplicate if its lowercase version has already appeared in the list.

For example, given the list:

Python
python
PYTHON
Java
java

The result should be:

Python
Java

The uniqueness check is done by comparing the strings in their lowercase format. You need to implement a solution that reads from standard input and writes the result to standard output.

Note: If there are no strings in the input, your program should produce no output.

inputFormat

The input begins with a single integer n (0 ≤ n ≤ 10⁵), indicating the number of strings. It is followed by n lines, each containing one string. Each string may contain alphabets and is non-empty.

Input is provided from stdin.

outputFormat

Output the unique strings (based on case-insensitive uniqueness) in the order of their first occurrence. Each string should be printed on a separate line. Output is printed to stdout.

## sample

5
Python
python
PYTHON
Java
java

Python
Java

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