Task: Question Generation
Input (English): Passage: From November 1943, during the seven-week Battle of Changde, the Chinese forced Japan to fight a costly war of attrition, while awaiting Allied relief. In January 1944, the Allies launched a series of attacks in Italy against the line at Monte Cassino and tried to outflank it with landings at Anzio. By the end of January, a major Soviet offensive expelled German forces from the Leningrad region, ending the longest and most lethal siege in history. The following Soviet offensive was halted on the pre-war Estonian border by the German Army Group North aided by Estonians hoping to re-establish national independence. This delay slowed subsequent Soviet operations in the Baltic Sea region. By late May 1944, the Soviets had liberated Crimea, largely expelled Axis forces from Ukraine, and made incursions into Romania, which were repulsed by the Axis troops. The Allied offensives in Italy had succeeded and, at the expense of allowing several German divisions to retreat, on 4 June, Rome was captured. The Allies had mixed success in mainland Asia. In March 1944, the Japanese launched the first of two invasions, an operation against British positions in Assam, India, and soon besieged Commonwealth positions at Imphal and Kohima. In May 1944, British forces mounted a counter-offensive that drove Japanese troops back to Burma, and Chinese forces that had invaded northern Burma in late 1943 besieged Japanese troops in Myitkyina. The second Japanese invasion of China aimed to destroy China's main fighting forces, secure railways between Japanese-held territory and capture Allied airfields. By June, the Japanese had conquered the province of Henan and begun a new attack on Changsha in the Hunan province.
Output (English): How many months after the Battle of Changde began did the Japanese launch an operation against Brtisih positions in Assam, India?