Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

Ex Input:
Sentence1: Plants that shed their leaves seasonally each year are called deciduous plants. 
Sentence2: vines shed their leaves seasonally each year.

Ex Output:
each


Ex Input:
Sentence1: Thrinaxodon, a small Lystrosaurus Zone cynodont, shows many of the characters of the group. 
Sentence2: Thrinaxodon is from the animal family that eventually evolved into mammals.

Ex Output:
Thrinaxodon


Ex Input:
Sentence1: Horned lizards are reptiles with tails and a scaled body. 
Sentence2: Lizards are protected by their unique body.

Ex Output:

lizards