Question: Who is Liu Sui's paternal grandfather?

Knowledge 1: Liu Sui
Liu Sui (died 154 BC) was the son of Liu You.When Emperor Wen of Han ascended to the throne in 180 BC, Sui was made the Prince of Zhao in place of Lü Lu while other relatives were given other principalities to rule at the end of Lü Clan Disturbance.During the reign of Emperor Jing of Han, key advisor Chao Cuo suggested that the emperor use past ignored offences committed by the princes to reduce size of their lands, and Sui lost the Changshan Commandery in this process.Out of anger at this decision by the emperor, Sui was persuaded to join the Rebellion of the Seven States.He allied with the Xiongnu forces and battled general Li Ji's forces.The Zhao forces were eventually wiped out by general Luan Bu followed by his conquest in the Qi state regions, and Sui committed suicide. [SEP] Knowledge 2: Liu You
Liu You (died 181 BC) was the sixth son of Emperor Gaozu of Han.He was made Prince of Huaiyang in 196 BC, and recreated as Prince Ji of Zhao two years later.You married Empress Dowager Lü's niece and was found to be having affairs with secret mistress.Empress Dowager Lü summoned him to the capital and imprisoned him there without food.While in prison, You made a song cursing the deeds which Empress Dowager Lü had done to the Liu family.He was afraid to commit suicide and ended up starving to death.
Knowledge 1: Liu Sui
Liu Sui (died 154 BC) was the son of Liu You.When Emperor Wen of Han ascended to the throne in 180 BC, Sui was made the Prince of Zhao in place of Lü Lu while other relatives were given other principalities to rule at the end of Lü Clan Disturbance.During the reign of Emperor Jing of Han, key advisor Chao Cuo suggested that the emperor use past ignored offences committed by the princes to reduce size of their lands, and Sui lost the Changshan Commandery in this process.Out of anger at this decision by the emperor, Sui was persuaded to join the Rebellion of the Seven States.He allied with the Xiongnu forces and battled general Li Ji's forces.The Zhao forces were eventually wiped out by general Luan Bu followed by his conquest in the Qi state regions, and Sui committed suicide. [SEP] Knowledge 2: Fujiwara no Nagara
, also known as Fujiwara no Nagayoshi, was a Japanese statesman, courtier and politician of the early Heian period.He was the grandfather of Emperor Yōzei.
Knowledge 1: Liu Sui
Liu Sui (died 154 BC) was the son of Liu You.When Emperor Wen of Han ascended to the throne in 180 BC, Sui was made the Prince of Zhao in place of Lü Lu while other relatives were given other principalities to rule at the end of Lü Clan Disturbance.During the reign of Emperor Jing of Han, key advisor Chao Cuo suggested that the emperor use past ignored offences committed by the princes to reduce size of their lands, and Sui lost the Changshan Commandery in this process.Out of anger at this decision by the emperor, Sui was persuaded to join the Rebellion of the Seven States.He allied with the Xiongnu forces and battled general Li Ji's forces.The Zhao forces were eventually wiped out by general Luan Bu followed by his conquest in the Qi state regions, and Sui committed suicide. [SEP] Knowledge 2: Liu Xiong
Liu Xiong was an official who lived during the Eastern Han dynasty of China.He was the father of Liu Hong and grandfather of the Shu Han warlord Liu Bei.According to the Three Kingdoms article, he is a descendant of Liu Sheng, Prince of Zhongshan.

Answer: Emperor Gaozu of Han