Definition: In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.
Input: Republican President Donald Trump and First Lady Melania Trump attended church services in observation of a special National Day of Prayer, which Trump previously declared, in support of the victims of Hurricane Harvey dwelling in the state of Texas, to 'uplift one another and assist those suffering from the consequences of this terrible storm.'
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
when was the last time a president declared a national day of prayer