
ZOJ Problem Set  2545
Amtel has announced that it will release a 128bit computer chip by 2010, a 256bit computer by 2020, and so on, continuing its strategy of doubling the wordsize every ten years. (Amtel released a 64bit computer in 2000, a 32bit computer in 1990, a 16bit computer in 1980, an 8bit computer in 1970, and a 4bit computer, its first, in 1960.) Amtel will use a new benchmark  the Factstone  to advertise the vastly improved capacity of its new chips. The Factstone rating is defined to be the largest integer n such that n! can be represented as an unsigned integer in a computer word. Given a year 1960 ≤ y ≤ 2160, what will be the Factstone rating of Amtel's most recently released chip?
InputThere are several test cases. For each test case, there is one line of input containing y. A line containing 0 follows the last test case.OutputFor each test case, output a line giving the Factstone rating.Sample Input1960 1981 0 Sample Output3 8 Source: University of Waterloo Local Contest 2005.09.24 