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: smell is used for finding food by some animals. 
Sentence2: Food includes small rodents and birds.

Ex Output:
food


Ex Input:
Sentence1: rain causes erosion. 
Sentence2: Soil Erosion Soil erosion is what happens when soil is washed or blown away.

Ex Output:
erosion


Ex Input:
Sentence1: Bird beaks are generally adapted for the food they eat. 
Sentence2: Birds eat food that they scavenge.

Ex Output:

Bird