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)

#include <bits/stdc++.h>

using namespace std;

#define endl "\n"
#define pb(s) push_back(s)
#define mp(a,b) make_pair(a,b)
#define f first
#define se second
#define ALL(v) v.begin(), v.end()
#define ALLA(arr, sz) arr, arr + sz
#define SORT(v) sort(ALL(v))
#define REVERSE(v) reverse(ALL(v))
#define SORTA(arr, sz) sort(ALLA(arr, sz))
#define REVERSEA(arr, sz) reverse(ALLA(arr, sz))
#define PI 3.14159265358979323846264338327950L
#define MOD 1000000007

typedef long long ll;

void solve(){
    int W,a,b;
    cin>>W>>a>>b;
    int firstL=a;
    int firstR=a+W;
    int secondL=b;
    int secondR=b+W;
    if(firstL>secondR){
        cout<<firstL-secondR<<endl;
    }
    else if(firstR<secondL){
        cout<<secondL-firstR<<endl;
    }
    else cout<<0<<endl;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    //int t;
    //cin>>t;
    //while(t--)
        solve();
    return 0;
}