Czech Technical University in Prague
ICPC Foundation
Czech ACM Chapter
Central Europe Regional Contest 2019
Zeldain Garden
garden.c, garden.cpp, Garden.java, garden.py
Boris is the chief executive officer of Rock Anywhere Transport (RAT) company which spe-
cializes in supporting music industry. In particular, they provide discount transport for many
popular rock bands. This time Boris has to move a large collection of quality Mexican concert
loudspeakers from the port on the North Sea to the far inland capital. As the collection is
expected to be big, Boris has to organize a number of lorries to assure smooth transport. The
multitude of lorries carrying the cargo through the country is called a convoy.
Boris wants to transport the whole collection in one go by a single convoy and without leaving
even a single loudspeaker behind. Strict E.U. regulations demand that in the case of large
transport of audio technology, all lorries in the convoy must carry exactly the same number of
pieces of the equipment.
To meet all the regulations, Boris would like to do some planning in advance, despite the fact that
he does not yet know the exact number of loudspeakers, which has a very significant influence
on the choices of the number and the size of the lorries in the convoy. To examine various
scenarios, for each possible collection size, Boris calculates the so-called "variability", which is
the number of different convoys that may be created for that collection size without violating
the regulations. Two convoys are different if they consist of a different number of lorries.
For instance, the variability of the collection of 6 loudspeakers is 4, because they may be evenly
divided into 1, 2, 3, or 6 lorries.
Input Specification
The input contains one text line with two integers N , M (1 ≤ N ≤ M ≤ 1012), the minimum
and the maximum number of loudspeakers in the collection.
Output Specification
Print a single integer, the sum of variabilities of all possible collection sizes between N and M ,
inclusive.
Sample Input 1
Output for Sample Input 1
25
9
Sample Input 2
Output for Sample Input 2
12 12
6
Sample Input 3
Output for Sample Input 3
555 666
852
