###Answer the question from the input provided. Please answer from input only.

###Input: The succession of Genghis Khan was already a significant topic during the later years of his reign, as he reached old age. The long running paternity discussion about Genghis' oldest son Jochi was particularly contentious because of the seniority of Jochi among the brothers. According to traditional historical accounts, the issue over Jochi's paternity was voiced most strongly by Chagatai. In The Secret History of the Mongols, just before the invasion of the Khwarezmid Empire by Genghis Khan, Chagatai declared before his father and brothers that he would never accept Jochi as Genghis Khan's successor. In response to this tension, and possibly for other reasons, Ögedei was appointed as successor.

Genghis Khan was aware of the friction between his sons (particularly between Chagatai and Jochi) and worried of possible conflict between them if he died. He therefore decided to divide his empire among his sons and make all of them Khan in their own right, while appointing one of his sons as his successor. Chagatai was considered unstable due to his temper and rash behavior, because of statements he made that he would not follow Jochi if he were to become his father's successor. Tolui, Genghis Khan's youngest son, was not to be his successor because he was the youngest and in the Mongol culture, youngest sons were not given much responsibility due to their age. If Jochi were to become successor, it was likely that Chagatai would engage in warfare with him and collapse the empire. Therefore, Genghis Khan decided to give the throne to Ögedei. Ögedei was seen by Genghis Khan as dependable in character and relatively stable and down to earth and would be a neutral candidate and might defuse the situation between his brothers.

Jochi died in 1226, during his father's lifetime. Some scholars, notably Ratchnevsky, have commented on the possibility that Jochi was secretly poisoned by an order from Genghis Khan. Rashid al-Din reports that the great Khan sent for his sons in the spring of 1223, and while his brothers heeded the order, Jochi remained in Khorasan. Juzjani suggests that the disagreement arose from a quarrel between Jochi and his brothers in the siege of Urgench. Jochi had attempted to protect Urgench from destruction, as it belonged to territory allocated to him as a fief. He concludes his story with the clearly apocryphal statement by Jochi: "Genghis Khan is mad to have massacred so many people and laid waste so many lands. I would be doing a service if I killed my father when he is hunting, made an alliance with Sultan Muhammad, brought this land to life and gave assistance and support to the Muslims." Juzjani claims that it was in response to hearing of these plans that Genghis Khan ordered his son secretly poisoned; however, as Sultan Muhammad was already dead in 1223, the accuracy of this story is questionable.

In August 1227, during the fall of Yinchuan, the capital of Western Xia, Genghis Khan died. The exact cause of his death remains a mystery, and is variously attributed to being killed in action against the Western Xia, illness, falling from his horse, or wounds sustained in hunting or battle. According to The Secret History of the Mongols Genghis Khan fell from his horse while hunting and died because of the injury. He was already old and tired from his journeys. The Galician–Volhynian Chronicle alleges he was killed by the Western Xia in battle, while Marco Polo wrote that he died after the infection of an arrow wound he received during his final campaign. Later Mongol chronicles connect Genghis' death with a Western Xia princess taken as war booty. One chronicle from the early 17th century even relates the legend that the princess hid a small dagger and stabbed him, though some Mongol authors have doubted this version and suspected it to be an invention by the rival Oirads.

Years before his death, Genghis Khan asked to be buried without markings, according to the customs of his tribe. After he died, his body was returned to Mongolia and presumably to his birthplace in Khentii Aimag, where many assume he is buried somewhere close to the Onon River and the Burkhan Khaldun mountain (part of the Kentii mountain range). According to legend, the funeral escort killed anyone and anything across their path to conceal where he was finally buried. The Genghis Khan Mausoleum, constructed many years after his death, is his memorial, but not his burial site.



###Question: The paternity of which of Genghis Khan's sons was disputed?

###Answer: {'answer':'Jochi'}