1929. Strength

Let us begin with a positive integer `N` and find the smallest positive integer which doesn't divide `N`. If we repeat the procedure with the resulting number, then again with the new result and so on, we will eventually obtain the number 2 (two). Let us define `"strength"(N)` as the length of the resulting sequence.

For example, for `N\ =\ 6` we obtain the sequence `6,\ 4,\ 3,\ 2` which consists of 4 numbers, thus `"strength"(6)\ =\ 4`.

Given two positive integers `A\ \ <\ \ B`, calculate the sum of strengths of all integers between `A` and `B` (inclusive), that is,

`"strength"(A)\ +\ "strength"(A\ +\ 1)\ +\ …\ +\ "strength"(B)`.

The first and only line of input contains two positive integers, `A` and `B` (`3\ ≤\ A\ <\ B\ <\ 10^17`).

The first and only line of output should contain the requested sum of strengths.

3 6

11

100 200

262