Introduction - If you have any usage issues, please Google them yourself
Series of very poor question written on the blackboard a positive integer N composed of a series, the following: two of them wipe each time the number of a, b, and then add a series number of a × b+1, it goes on until the rest of the board of a number, according to this mode of operation in all the resulting numbers, the biggest for the max, the smallest for the min, then the series range is defined as M = max-min.