Problems

# Sum of even numbers

# Sum of even numbers

Find the sum of even numbers on a segment from **a** to **b** inclusively.

#### Input

Two integers **а** and **b** (**а** ≤ **b**), no more than `10`

by absolute value.^{9}

#### Output

Print the sum of even numbers on a segment from **a** to **b** inclusively.

Input example #1

1 5

Output example #1

6