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: boiling is when liquids are heated above their boiling point. 
Sentence2: If the pressure is reduced, the boiling point is lowered.

Ex Output:
boiling


Ex Input:
Sentence1: Sex hormones are chemical messengers that control sexual development and reproduction. 
Sentence2: Androgens are male sex hormones.

Ex Output:
Sex


Ex Input:
Sentence1: Sex hormones are chemical messengers that control sexual development and reproduction. 
Sentence2: Sex hormones control sexual development in male and female bodies.

Ex Output:

control