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;


namespace ConsoleApplication1
{

    // input W a b

    class NarrowRectanglesEasy
    {
        static void Main(string[] args)
        {
            // get a integer
            // int a = int.Parse(Console.ReadLine());
            // get two integers separated with half-width break
            string[] input = Console.ReadLine().Split(' ');
            int W = int.Parse(input[0]);
            int a = int.Parse(input[1]);
            int b = int.Parse(input[2]);


            if (a <= b)
            {

                if ((a + W) >= b) { Console.WriteLine(0); }
                if ((a + W) < b) { Console.WriteLine(Math.Abs(b - (a + W))); }

            }
            else {
                if ((b + W) >= a) { { Console.WriteLine(0); } }
                if ((b + W) < a) { { Console.WriteLine(Math.Abs(a-(b+W))); } }
            }

        }

    }
}