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:

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.

-----Sample Input-----
3 2 6

-----Sample Output-----
1

This input corresponds to the figure in the statement. In this case, the second rectangle should be moved to the left by a distance of 1.

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