Hello Tamers. This is Digital Administration.

We figured out that the number of item stacks for the Teacher's Day event wasn't enough,

and we are going to change the stacks to 999 through a live patch.

The patch is scheduled to be applied in-game on 13 May 06:00 (PST) after the server reset, 
and a client restart is required.

Items scheduled to change stacks: 
[Children's Envelopes],[Children's Letter Papers],[Children's Pens], [Children's letters], [Ballpoint pen], and [A Piece of Carnation]

Changed the stacks from 100 to 999

thank you!