Problem:
Score : 200 points

Problem Statement

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 1

3 2 6

Sample Output 1

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.

Sample Input 2

3 1 3

Sample Output 2

0

The rectangles are already connected, and thus no move is needed.

Sample Input 3

5 10 1

Sample Output 3

4

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System.Linq;
using System;//.Linq;
class A{
static void Main()
{
int []a=Console.ReadLine().Split().Select(int.Parse).ToArray();
int s=a[2]-a[1]-a[0];
int d=a[1]-a[2]-a[0];
if(d<0&&s<0){Console.WriteLine("0");}
else if(d>0&&s<0){Console.WriteLine(d);}
else if(d<0&&s>0){Console.WriteLine(s);}
else if(d<s){Console.WriteLine(s);}else{ Console.WriteLine(d);}
}
}