Gears

A watchmaker owns a lathe that can make gears with anywhere from $M$ to $N$ teeth.

Write a program that determines how many different gear ratios (transmissions built from two gears) can be produced on this machine. Two gear ratios are counted as different when their value — the number of teeth on the first gear divided by the number of teeth on the second gear — is different.

The first line contains two space-separated integers $M$ and $N$ ($1 \le M \le N \le 1000$), the minimum and maximum number of teeth on the gears that this machine can make.

Print the number of different gear ratios that can be produced, on a single line.