In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Example: what is the first event mentioned?, Context: The Russian Revolution is the series of revolutions in Russia in 1917, which destroyed the Tsarist autocracy and led to the creation of the Soviet Union. Following the abdication of Nicholas II of Russia, the Russian Provisional Government was established. In October 1917, a red faction revolution occurred in which the Red Guard, armed groups of workers and deserting soldiers directed by the Bolshevik Party, seized control of Saint Petersburg (then known as Petrograd) and began an immediate armed takeover of cities and villages throughout the former Russian Empire.
Example solution: Russian Revolution
Example explanation: This is a good example, and the Russian Revolution is the first event mentioned.

Problem: The Soviets had to reach a peace agreement with which other nation before they could commit to invading Poland?, Context: The stated clauses of the Nazi-Soviet non-aggression pact were a guarantee of non-belligerence by each party towards the other, and a written commitment that neither party would ally itself to, or aid, an enemy of the other party. In addition to stipulations of non-aggression, the treaty included a secret protocol that divided territories of Romania, Poland, Lithuania, Latvia, Estonia, and Finland into German and Soviet "spheres of influence", anticipating potential "territorial and political rearrangements" of these countries. Thereafter, Germany invaded Poland on 1 September 1939. After the Soviet–Japanese ceasefire agreement took effect on 16 September, Stalin ordered his own invasion of Poland on 17 September. Part of southeastern (Karelia) and Salla region in Finland were annexed by the Soviet Union after the Winter War. This was followed by Soviet annexations of Estonia, Latvia, Lithuania, and parts of Romania (Bessarabia, Northern Bukovina, and the Hertza region). Concern about ethnic Ukrainians and Belarusians had been proffered as justification for the Soviet invasion of Poland. Stalin's invasion of Bukovina in 1940 violated the pact, as it went beyond the Soviet sphere of influence agreed with the Axis.
Solution: Japanese