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: Accepted)

//#define _CRT_SECURE_NO_WARNINGS
#include "bits/stdc++.h"

#define rep(i,n) for(ll (i)=0;(i)<(ll)(n);(i)++)
#define all(x) (x).begin(),(x).end()
#define MOD 1000000007LL
#define INF (1LL<<60LL)
#define int long long
typedef long long ll;

using namespace std;


signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int w, a, b;
	cin >> w >> a >> b;
	int ans = 0;
	if (a + w <= b) ans = b - (a + w);
	else if (b + w <= a) ans = a - (b + w);
	cout << ans << endl;
}