最多约数问题:正整数x 的约数是能整除x 的正整数。正整数x 的约数个数记为div(x)。例如，1，2，

5，10 都是正整数10 的约数，且div(10)=4。设a 和b 是2 个正整数，a≤b，找出a 和b

之间约数个数最多的数x。-A maximum of about a few issues: positive integers x, some number is divisible by x, can be a positive integer. About the number of positive integers x, the number denoted div (x). For example, 1,2, 5,10 are about 10 the number of positive integers, and div (10) = 4. Set a and b are two positive integers, a ≤ b, find out about the number between a and b the number of the largest number of x.