Task: Question Answering
Input (English): Passage: When an ally of the Ü-Tsang ruler threatened destruction of the Gelugpas again, the fifth Dalai Lama Lozang Gyatso pleaded for help from the Mongol prince Güshi Khan (1582–1655), leader of the Khoshut (Qoshot) tribe of the Oirat Mongols, who was then on a pilgrimage to Lhasa. Güshi Khan accepted his role as protector, and from 1637–1640 he not only defeated the Gelugpas' enemies in the Amdo and Kham regions, but also resettled his entire tribe into Amdo. Sonam Chöpel urged Güshi Khan to assault the Ü-Tsang king's homebase of Shigatse, which Güshi Khan agreed upon, enlisting the aid of Gelug monks and supporters. In 1642, after a year's siege of Shigatse, the Ü-Tsang forces surrendered. Güshi Khan then captured and summarily executed Karma Tenkyong, the ruler of Ü-Tsang, King of Tibet.Soon after the victory in Ü-Tsang, Güshi Khan organized a welcoming ceremony for Lozang Gyatso once he arrived a day's ride from Shigatse, presenting his conquest of Tibet as a gift to the Dalai Lama. In a second ceremony held within the main hall of the Shigatse fortress, Güshi Khan enthroned the Dalai Lama as the ruler of Tibet, but conferred the actual governing authority to the regent Sonam Chöpel. Although Güshi Khan had granted the Dalai Lama "supreme authority" as Goldstein writes, the title of 'King of Tibet' was conferred upon Güshi Khan, spending his summers in pastures north of Lhasa and occupying Lhasa each winter. Van Praag writes that at this point Güshi Khan maintained control over the armed forces, but accepted his inferior status towards the Dalai Lama. Rawski writes that the Dalai Lama shared power with his regent and Güshi Khan during his early secular and religious reign. However, Rawski states that he eventually "expanded his own authority by presenting himself as Avalokiteśvara through the performance of rituals," by building the Potala Palace and other structures on traditional religious sites, and by emphasizing lineage reincarnation through written biographies. Goldstein states that the government of Güshi Khan and the Dalai Lama persecuted the Karma Kagyu sect, confiscated their wealth and property, and even converted their monasteries into Gelug monasteries. Rawski writes that this Mongol patronage allowed the Gelugpas to dominate the rival religious sects in Tibet. 
Question: What was the last name of the person who was on a pilgrimage to Lhasa?
Output (English): Khan.