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 Go (1.14.1) (judge verdict: Accepted)

package main
 
import (
  "fmt"
)
 
func main() {
  var W, a, b int
  fmt.Scan(&W)
  fmt.Scan(&a)
  fmt.Scan(&b)
  
  ans := abs(a - b)
  if ans <= W {
    ans = 0
  } else {
    ans -= W
  }
  fmt.Printf("%d\n", ans)
}

func abs(a int) int {
  if a < 0 {
    a *= -1
  }
  return a
}