Case-Insensitive Duplicate Plate IDs

You are given a list of plate IDs. Your task is to determine if there exists any pair of plate IDs that are identical when compared in a case-insensitive manner. In other words, convert each plate ID to lowercase and check if any two are the same.

Example:

If the plate IDs are: AbC, aBC, xyz, XYz, then after converting to lowercase they become: abc, abc, xyz, xyz. Since there are duplicates, the output should be YES.

Note: The comparison is case-insensitive. Even an empty string is a valid plate ID.

inputFormat

The input is read from stdin and has the following format:

• The first line contains a single integer \( n \), the number of plate IDs.
• The following \( n \) lines each contain a plate ID as a string. A plate ID may be empty or contain spaces.

outputFormat

Output a single line to stdout containing YES if there is at least one pair of duplicate plate IDs when compared case-insensitively; otherwise, output NO.

4
AbC
aBC
xyz
XYz

YES