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: Heterotrophs are living things that cannot make their own food. 
Sentence2: food contains organic molecules.

Ex Output:
food


Ex Input:
Sentence1: high mountains with well-rounded peaks can be formed by collision of crustal plates. 
Sentence2: high mountains with well-rounded peaks can be formed by collision of plate tectonics.

Ex Output:
collision


Ex Input:
Sentence1: Jaws also make cartilaginous fish excellent predators. 
Sentence2: Jaws make some carnivores excellent predators.

Ex Output:

Jaws