For any sequence of real numbers A=\left(a_{1}, a_{2}, a_{3}, \ldots\right), define \triangle A to be the sequence \left(a_{2}-a_{1}, a_{3}-a_{2}, a_{4}-a_{3}, \ldots\right), whose n^{\text {th }} term is a_{n+1}-a_{n}. Suppose that all of the terms of the sequence \triangle(\triangle A) are 1, and that a_{19}=a_{92}=0. Find a_{1}.