题目描述
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
输入格式
见题面
输出格式
见题面