Definition: 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.
Input: Sentence1: Menstruation occurs after the secretion of progesterone stops. 
Sentence2: Menopause occurs when  secretion of progesterone stops.

progesterone