How to add a word in the middle of certain lines in Notepad++?

Question

Notepad++

Let's say I have code:

{
        X, Y
        X, Y
}

How to add letter Z in the middle of both lines X, Y?
To make it happen:

{
X, Z, Y
X, Z, Y
}

Answer 1

Find: ^\h*X,
Replace:$0 Z,