There are two integers L and R, you'll have to count how many odd numbers are there within the range from L to R inclusive.

All of you know what is an odd number. A number that is not divisible by 2 is called an odd number.

Input

The only line contain two integers L, R.

Constraints

0 <= L <= R <= 100000000

Output

Print the count of odd numbers from L to R inclusive.

Example

Input:
2 3

Output:
1

[ Original Setter of this Problem Dhruba Mitra, RUET ]