There were 70 nations that descended from the sons of Noach (Noah). Fourteen nations came from Yefes (Jepheth). Thirty came from Cham (Ham) [Bereishis (Genesis) 10:1-32]. How many came from his third son Shem?
14 sons + 30 sons = 44 total sons from the Yefes and Cham
70 sons – 44 sons = 26 sons from Shem