using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
namespace AtCoder {
    class MainClass {
        public static void Main(string[] args) { new MainClass().stream(); }
        IO io=new IO();  void stream() { solve(); io.writeFlush();}

        int W, a, b;
        void solve() {
            W = io.nextInt();
            a = io.nextInt();
            b = io.nextInt();

            if (a > b) {
                int tmp = a;
                a = b; b = tmp;
            }

            int ans = Math.Max(0, b - (a + W));

            io.write(ans);

        }
        class IO {
            string[] nextBuffer; int BufferCnt; char[] cs = new char[] { ' ' };
            StreamWriter sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            public IO() { nextBuffer = new string[0]; BufferCnt = 0; Console.SetOut(sw); }
            public string next() {
                if (BufferCnt < nextBuffer.Length) return nextBuffer[BufferCnt++];
                string st = Console.ReadLine();
                while (st == "") st = Console.ReadLine();
                nextBuffer = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
                BufferCnt = 0;
                return nextBuffer[BufferCnt++];
            }
            public char nextChar() { return char.Parse(next()); }
            public int nextInt() { return int.Parse(next()); }
            public long nextLong() { return long.Parse(next()); }
            public double nextDouble() { return double.Parse(next()); }
            public string[] array() { return Console.ReadLine().Split(' '); }
            public char[] arrayChar() { return Array.ConvertAll(array(), char.Parse); }
            public int[] arrayInt() { return Array.ConvertAll(array(), int.Parse); }
            public long[] arrayLong() { return Array.ConvertAll(array(), long.Parse); }
            public double[] arrayDouble() { return Array.ConvertAll(array(), double.Parse); }
            public void write<T>(T v) { Console.WriteLine(v);  }
            public void write<T>(T[] v) {foreach (T n in v) Console.WriteLine(n); }
            public void writeFlush() { Console.Out.Flush(); }
        }


        class Mathf {
            public int mod = 1000000007;//10^9+7
            public long Pow(long a, long b) {
                if (b == 0) return 1;
                if (b % 2 == 1) return (a % mod * Pow(a % mod, b - 1) % mod) % mod;
                else return Pow(a * a % mod, b / 2) % mod;
            }
            public long Fact(long n) { return n != 0 ? (n % mod * (Fact(n - 1) % mod) % mod) : 1; }
            public long C(long n, long r) {
                if (r == 0 || n == r) return 1;
                else return (Fact(n) % mod * Pow((Fact(n - r) % mod * Fact(r) % mod) % mod, mod - 2) % mod) % mod;
            }
            public int GCD(int a, int b) { if (a < b) Swap(ref a, ref b); return b == 0 ? a : GCD(b, a % b); }
            public int GCD(int[] array) { return array.Aggregate((v, next) => GCD(v, next)); }
            public void Swap<T>(ref T a, ref T b) { T tmp = a; a = b; b = tmp; }
        }
    }
}

Measured memory_bytes: 11092