Starting with letter A, and arranging the other four letters, there are 4!=24 words. These are the first 24 words. Then starting with G, and arranging A,A,I and N in different ways, there are 2!1!1!4!=12 words. Next the 37th word starts with I. There are again 12 words starting with I. This accounts up to the 48th word. The 49th word is NAAGI.