In mathematics, the function d(n) denotes the number of divisors of a positive integer n.
For example, d(12)=6 because 1, 2, 3, 4, 6 and 12 are all divisors of 12.
In this problem, you are given l, r and k. Your task is to calculate the following:
(∑_i=lrd(ik)) mod998,244,353.