15106번 - Fear Factoring 다국어

The Slivians are afraid of factoring; it’s just, well, difficult.

Really, they don’t even care about the factors themselves, just how much they sum to.

We can define F(n) as the sum of all of the factors of n; so F(6) = 12 and F(12) = 28. Your task is, given two integers a and b with a ≤ b, to calculate

\[S=\sum_{a \le n \le b}{F(n)}\]

The input consists of a single line containing space-separated integers a and b (1 ≤ a ≤ b ≤ 10¹²; b − a ≤ 10⁶).

Print S on a single line.