import Foundation
func toTuple<T>(_ args: [T]) -> (T, T, T) { (args[0], args[1], args[2]) }
func readInts() -> [Int] { readLine()!.split(separator: " ").map { Int($0)! } }

let (w, a, b) = toTuple(readInts())
let d = max(a, b) - (min(a, b) + w)
print(d < 0 ? 0 : d)