object MainKt {
  @JvmStatic fun main(args:Array<String>) {
    val (W,a,b)=readLine()!!.split(" ").map{it.toInt()}
    val (norm_a,norm_b)=if(a<b) Pair(a,b) else Pair(b,a)  
   println(if(norm_a<=norm_b && norm_b<=norm_a+W) 0 else norm_b-(norm_a+W))
  }
}