Sharing Letter M?

We talk a lot about sharing with Maddox. So far, MK has agreed to share most everything except her beloved shoes. On Friday, she was doing an alphabet puzzle. She got to the letter "M" and shouted, "Hey, Mom, look it is letter M for Mason-Kate!" Oh, she was so excited with this discovery! I said, "Yes, the letter M is for Mason-Kate and Maddox too!" She got a peculiar look on her face and there was a long pause. I said, "Mason-Kate, M is for Maddox too." She replied, "We can't share the letter M, mom. God will have to make baby Maddox her own M. If we share my letter M and I cut it in half, it would look like the letter N!"