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: People of all ages and activity levels perspire or sweat. 
Sentence2: Perspiration reduces body heat.

Ex Output:
perspire


Ex Input:
Sentence1: Climate is the average weather in an area over a long period of time. 
Sentence2: the average weather in Taiwan over a long period of time is subtropical.

Ex Output:

average


