In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it, i.e., the proper nouns in the passage. Your job is to determine whether information from more than one term is needed to answer the question. Indicate your choice as 'a' for Yes or 'b' for No.

Question: How many countries total were included in the Treaty? Passage:The garden already existed at least in the early 18th century. During the Austrian occupation of northern Serbia 1717-39, several hospitals were established in Belgrade, including the Great military hospital. Based on the Austrian plans, the hospital was set outside of the Belgrade Fortress ("Danubian" or "German Belgrade"), in the Serbian part of the city. As shown on the map of Belgrade by Nicolas Francois de Spar, the Tsarigrad Road began at the Wurttemberg Gate (Stambol Gate), at the modern Republic Square, and headed towards "Marko's cemetery" in Tasmajdan. The hospital was situated on the road's right side, where the modern Stari Dvor is located. Behind the hospital there was a large garden, predecessor of the modern park, and further behind it, across the road was the military cemetery. Later "Marko's market" developed on the spot and today it is the area surrounding the House of the National Assembly of Serbia. After Austria lost the Austro-Turkish War of 17371739, the northern Serbia, including Belgrade, was returned to the Turks. One of the provisions of the 1739 Treaty of Belgrade stated that Austria had to demolish all the fortifications and military and civilian buildings it has constructed during the occupation. Many Baroque buildings were demolished. However, Austria didn't demolish the buildings outside of the fortress walls, including the Great military hospital, which, albeit as a ruin, survived until the next Austrian occupation in 1788.
b