p03778 AtCoder Beginner Contest 056 - NarrowRectanglesEasy
AtCoDeer the deer found two rectangles lying on the table, each with height 1 and width W. If we consider the surface of the desk as a two-dimensional plane, the first rectangle covers the vertical range of [0,1] and the horizontal range of [a,a+W], and the second rectangle covers the vertical range of [1,2] and the horizontal range of [b,b+W], as shown in the following figure:

<image>

AtCoDeer will move the second rectangle horizontally so that it connects with the first rectangle. Find the minimum distance it needs to be moved.

Constraints

* All input values are integers.
* 1≤W≤10^5
* 1≤a,b≤10^5

Input

The input is given from Standard Input in the following format:


W a b


Output

Print the minimum distance the second rectangle needs to be moved.

Examples

Input

3 2 6


Output

1


Input

3 1 3


Output

0


Input

5 10 1


Output

4
```python
W, a, b = map(int, input().split())

abs = max(a, b) - min(a, b) - W

print(max(0, abs))
```