CF204A Little Elephant and Interval

Description

The Little Elephant very much loves sums on intervals. This time he has a pair of integers $ l $ and $ r $ $ (l

Input Format

The single line contains a pair of integers $ l $ and $ r $ $ (1

Output Format

On a single line print a single integer — the answer to the problem.

Explanation/Hint

In the first sample the answer includes integers 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44.