Definition: In this task, you're given a question, along with a context passage. The passage will not have a direct answer to the question, but can include some information and a clue for the answer. Assuming you can only obtain information about one entity in the passage, your job is to determine whether information from the passage can be used to answer the question. Indicate your choice as `a` for Yes or `b` for No.
Input: Question: What years did Ulysses S. Grant serve as president? Passage:The establishment of Decoration Day as an official government holiday (by proclamation, not by law) swiftly occurred, and the holiday was almost immediately a popular one. At Arlington cemetery, the number of people attending the annual event swiftly overwhelmed the limited facilities. The first Decoration Day event was held in front of Arlington House. James A. Garfield, a former Major General in the Union Army (and future President of the United States), addressed a "large crowd" from the mansion's back steps. The following year, President Ulysses S. Grant closed the federal government for the holiday, and most businesses followed, which greatly contributed to attendance at the cemetery. A dais seating 400 people was erected in what remained of "the Grove" at the rear of Arlington House to accommodate speakers and dignitaries—which, for the first time, included President Grant. The Civil War Unknowns Monument, which was located south-southwest of Arlington House, was covered by a canopy. Several American flags hung from the canopy, red-white-and-blue bunting was draped along the monument's top, and numerous floral tributes were laid against it. An estimated 25,000 people attended the event throughout the day. Two sites for ceremonies were used in 1870. A very large speakers' dais was erected near the Sheridan Gate and McClellan Gate on the cemetery's east side, and used for speeches throughout the day. For the more important speakers, a second dais seating 200 was erected at the rear of Arlington House (although not with "the Grove"). A stand, permitting the seating of 500, was built nearby for a grand chorus (which sang for the crowd). Again, the Civil War Unknowns Monument was canopied and decorated. About 20,000 people attended the event that year, with rain keeping the numbers low. In 1871, the speakers' dais moved back to "the Grove" and expanded to accommodate 300 people. Frederick Douglass, the former African American slave and abolitionist, was the featured speaker that year. "Hundreds" of people attended his address, including President Grant. The dais moved again in 1872, this time to a location a few yards to the south of the Civil War Unknowns Monument. The dais was slightly reduced in size so that it only sat 200, but it now included a thrust on which stood a speaker's podium. More than 5,000 people attended the 1872 event.


b