quick question about postage for square invites

I just got an invitation in the mail that's square.

I'm just wondering - on the response envelope (which is also square), there's only 1 forever stamp on it. Does that cover the extra postage for the square, or do I need to put more postage on it? tia!

The response envelope is tiny thats why .44 covers it....

Square invites are more money because they are much larger and dont fit through the machine usually.