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

###Input: The Chinese medical tradition of the Yuan had "Four Great Schools" that the Yuan inherited from the Jin dynasty. All four schools were based on the same intellectual foundation, but advocated different theoretical approaches toward medicine. Under the Mongols, the practice of Chinese medicine spread to other parts of the empire. Chinese physicians were brought along military campaigns by the Mongols as they expanded towards the west. Chinese medical techniques such as acupuncture, moxibustion, pulse diagnosis, and various herbal drugs and elixirs were transmitted westward to the Middle East and the rest of the empire. Several medical advances were made in the Yuan period. The physician Wei Yilin (1277–1347) invented a suspension method for reducing dislocated joints, which he performed using anesthetics. The Mongol physician Hu Sihui described the importance of a healthy diet in a 1330 medical treatise.

Western medicine was also practiced in China by the Nestorian Christians of the Yuan court, where it was sometimes labeled as huihui or Muslim medicine. The Nestorian physician Jesus the Interpreter founded the Office of Western Medicine in 1263 during the reign of Kublai. Huihui doctors staffed at two imperial hospitals were responsible for treating the imperial family and members of the court. Chinese physicians opposed Western medicine because its humoral system contradicted the yin-yang and wuxing philosophy underlying traditional Chinese medicine. No Chinese translation of Western medical works is known, but it is possible that the Chinese had access to Avicenna's The Canon of Medicine.

The Mongol rulers patronized the Yuan printing industry. Chinese printing technology was transferred to the Mongols through Kingdom of Qocho and Tibetan intermediaries. Some Yuan documents such as Wang Zhen's Nong Shu were printed with earthenware movable type, a technology invented in the 12th century. However, most published works were still produced through traditional block printing techniques. The publication of a Taoist text inscribed with the name of Töregene Khatun, Ögedei's wife, is one of the first printed works sponsored by the Mongols. In 1273, the Mongols created the Imperial Library Directorate, a government-sponsored printing office. The Yuan government established centers for printing throughout China. Local schools and government agencies were funded to support the publishing of books.

One of the more notable applications of printing technology was the chao, the paper money of the Yuan. Chao were made from the bark of mulberry trees. The Yuan government used woodblocks to print paper money, but switched to bronze plates in 1275. The Mongols experimented with establishing the Chinese-style paper monetary system in Mongol-controlled territories outside of China. The Yuan minister Bolad was sent to Iran, where he explained Yuan paper money to the Il-khanate court of Gaykhatu. The Il-khanate government issued paper money in 1294, but public distrust of the exotic new currency doomed the experiment.

Politically, the system of government created by Kublai Khan was the product of a compromise between Mongolian patrimonial feudalism and the traditional Chinese autocratic-bureaucratic system. Nevertheless, socially the educated Chinese elite were in general not given the degree of esteem that they had been accorded previously under native Chinese dynasties. Although the traditional Chinese elite were not given their share of power, the Mongols and the Semuren (various allied groups from Central Asia and the western end of the empire) largely remained strangers to the mainstream Chinese culture, and this dichotomy gave the Yuan regime a somewhat strong "colonial" coloration. The unequal treatment is possibly due to the fear of transferring power to the ethnic Chinese under their rule. The Mongols and Semuren were given certain advantages in the dynasty, and this would last even after the restoration of the imperial examination in the early 14th century. In general there were very few North Chinese or Southerners reaching the highest-post in the government compared with the possibility that Persians did so in the Ilkhanate. Later the Yongle Emperor of the Ming dynasty also mentioned the discrimination that existed during the Yuan dynasty. In response to an objection against the use of "barbarians" in his government, the Yongle Emperor answered: "... Discrimination was used by the Mongols during the Yuan dynasty, who employed only "Mongols and Tartars" and discarded northern and southern Chinese and this was precisely the cause that brought disaster upon them".



###Question: What was the Yuan's paper money called?

###Answer: {'answer':'chao'}