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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <string>
using namespace std;
int main(){
	
	int W,a,b;
	cin>>W>>a>>b;
	//if(b-a>0 && b-(a+W)>0){//
	if(b>a && b<a+W /*|| a<b+W && a+W>b+W*/){	
		cout<<(a+W)-b<<endl;
	}
	if(a<b+W && a+W>b+W){
		cout<<(b+W)-a<<endl;
	}
	if(a+W<b){
		cout<<b-(a+W)<<endl;
	}
	if(a>b+W){
		cout<<a-(b+W)<<endl;
	}
	if(a+W==b || b+W==a){
		cout<<0;
	}
	return 0;
}