Problems
Sum of odd numbers
Sum of odd numbers
Find the sum of odd numbers in the range from $a$ to $b$.
\InputFile
Two integers $a$ and $b$, not greater than $10^9$ by absolute value.
\OutputFile
Print the sum of odd numbers in the range from $a$ to $b$.
Input example #1
2 5
Output example #1
8
Input example #13
-1987655734 1999999734
Output example #13
12305904774248000