Meet M & M by Pat Ross [9780140387315]

Mandy and Mimi are best friends. They look alike, have the same tooth missing, and they're also neighbors--which means fun is never far away. But one day everything goes wrong. They argue about what games to play, how to play them, and even where to play! Mimi storms upstairs to apartment 3B, while Mandy sulks at home in 2B. Can M and M find a way to meet halfway?