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.io.File;
import java.io.FileInputStream;
import java.util.NoSuchElementException;
import java.util.Scanner;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Deque;
import java.util.HashMap;
import java.util.List;
import java.util.Map.Entry;

public class Main {
	
	public static void main(String[] args) throws IOException {
		//File file = new File("input.txt");
		//Scanner sc = new Scanner(file);
		Scanner sc = new Scanner(System.in);
		
		int W = sc.nextInt();
		int a = sc.nextInt();
		int b = sc.nextInt();
		
		if(b >= a + W) System.out.println((b - (a + W)));
		else if(a >= b + W) System.out.println((a - (b + W)));
		else System.out.println(0);
	}
}