Who invented the abacus

Liu Hong, the word Yuanzhuo, the Eastern Han Dynasty Taishan County, Mengyin County (today's Linyi City, Shandong Province, Mengyin County) people, the Eastern Han Dynasty, King Lu Liu Xing descendants, is China's ancient outstanding astronomer and mathematician, the inventor of bead counting and the theory of the moon's motion inhomogeneity discoverer, was honored by the later generations of the "abacus saint".