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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int main(void){
    int width;
    int a,b;

//    printf("Input the width of square:");
    scanf("%d",&width);
  //  printf("Input the x coodinates of the under square:");
    scanf("%d",&a);
    //printf("Input the x coodinates of the upper square:");
    scanf("%d",&b);
    if(a<b&&b<a+width){
        printf("0");
    }
    else if(b<a&&a<b+width){
        printf("0");
    }
    else if(a+width<b){
        printf("%d",b-(a+width));
    }
    else if(b+width<a){
        printf("%d",a-(b+width));
    }
    return 0;
}