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:

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

inputFormat

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

outputFormat

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

样例

3 2 6

1