Description

Calculate the sum of all odd numbers between non-negative integers m and n (inclusive), where m is not greater than n, and n is not greater than 300. For example, if m=3 and n=12, the sum would be: 3+5+7+9+11=35.

Input Format

Two numbers m and n, separated by a space, where 0≤m≤n≤300.

Output Format

Output a single line containing an integer, representing the sum of all odd numbers between m and n (inclusive).

Sample

7 15

55