Description

For an integer $n$, if there exist two non-negative integers $x, y$ such that $n = x^2 - y^2$, then $n$ is called a Couple number.

Given $a, b$, find how many Couple numbers are in the range $[a, b]$.

Input Format

The input contains one line with two integers $a, b$.

Output Format

Output one line with a single integer representing the answer.

1 10

7

Hint

Constraints

For all test points, it is guaranteed that $-10^7 \le a < b \le 10^7$, $b - a \le 10^7$.

Translated by ChatGPT 5