Random Acts of Kindness Day
A teacher always finds greater satisfaction when their students surpass them…
Around the world, there are many holidays, some of which are not widely known. Among these is Groundhog Day, although it became more famous after the release of the movie with the same name. Similarly, the Spring Equinox and Winter Solstice are better known due to the introduction of daylight saving time and the annual adjustments it brings. Another lesser-known holiday is Random Acts of Kindness Day! This holiday remains quite obscure (at least until this problem brought it to light), and people celebrate it on different days. However, since there are only 365 days in a year (ignoring leap years), sometimes this holiday coincides for two different people. If they happen to be together on this day, it can create truly joyful moments for those around them, but only for that day…
For Anton and Vitaliy, their next shared Random Acts of Kindness Day occurred during the "Winter Programming School 2011" in Kharkiv. They decided to commemorate this coincidence by presenting simple problems to the school's participants. They saved one of these problems because, even on this special day, it seemed too simple to them. But we decided to unveil this "hidden" problem.
Here it is: "Find the sum of all distinct natural numbers from L to R inclusive."
Input
The input consists of a single line containing two integers L and R (1 ≤ L ≤ R ≤ 10^9).
Output
Output a single number: the solution to the problem.