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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Map;
import java.util.HashMap;

public class Main
{
    int w, a, b;
    
    public static void main(String args[])
    {
	new Main().solve();
    }
    
    void solve()
    {
	in();

	if(a > b) {
	    int tmp = a;
	    a = b;
	    b = tmp;
	}
	
	out(b - (a + w));
    }

    void in()
    {
	Scanner sc = new Scanner(System.in);
	w = sc.nextInt();
	a = sc.nextInt();
	b = sc.nextInt();
    }

    void out()
    {
	
    }
    
    void out(int n)
    {
	if(n > 0) System.out.println(n);
	else      System.out.println(0);
    }

    void out(char c)
    {
	System.out.print(c);
    }
    
    void out(String s)
    {
	System.out.println(s);
    }
}