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: Consider Input: Sentence1: Every photograph is produced by a camera. 
Sentence2: Photographers record images.

Output: photograph


Input: Consider Input: Sentence1: Endocrine glands include the pituitary, thyroid, parathyroid, adrenal, pineal and thymus glands. 
Sentence2: Some pituitary hormones can control the thyroid gland.

Output: thyroid


Input: Consider Input: Sentence1: If a single base is altered, a point mutation is generated. 
Sentence2: a point mutation allows for both asexual and sexual reproduction.


Output: mutation