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.

Example input: This list contains the top 25 accounts with the most followers on the social photo-sharing platform Instagram. As of May 2018, the most followed user is Instagram's own account, with over 235 million followers. Selena Gomez is the most followed individual, with over 137 million followers. Ten accounts have exceeded 100 million followers on the site.
Example output: who has the maximum number of followers on instagram
Example explanation: The answer is talking about the Instagram accounts that have the most followers. The question asking about the maximum number of followers. So this is a good example.
Q: From July 17 to August 2, 1945, the victorious Allies reached the Potsdam Agreement on the fate of postwar Europe, calling for the division of defeated Germany into four temporary occupation zones (thus re-affirming principles laid out earlier by the Yalta Conference). These zones were located roughly around the then-current locations of the allied armies. Also divided into occupation zones, Berlin was located 100 miles (160 km) inside Soviet-controlled eastern Germany. The United States, United Kingdom, and France controlled western portions of the city, while Soviet troops controlled the eastern sector.
A:
how did the location of berlin enable the soviets to blockade the city successfully