In this task, you are given two sentences in the English language (Sentence 1 and Sentence 2). Your task is to identify the connecting word between the two sentences.

Ex Input:
Sentence 1:Reliability depends not wholly on the developer but at times on the compatibility between a database and an OS version . Sentence 2:For example , the widely used MS Access database system had a compatibility issue when Windows XP machines were updated to a newer Windows OS .

Ex Output:
for example


Ex Input:
Sentence 1:Sandra , for the first time during her career , now participated actively in composing and writing the album . Sentence 2:Therefore , the lyrics of the songs are more personal , with Sandra revisiting her childhood and all her sad experiences in them .

Ex Output:
therefore


Ex Input:
Sentence 1:This principle ( or , theorem ) can be generalized . Sentence 2:Thus , let us consider a system S in the form of a closed domain of finite volume in the Euclidean space .

Ex Output:

thus