using System; using System.Collections.Generic; using System.Linq; using System.IO; using System.Text; using System.Numerics; namespace Solver { class Program { const int M = 1000000007; const double eps = 1e-9; static int d; static void Main() { var sw = new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false }; var sc = new Scan(); d = sc.Int; var h = new int[3]; for (int i = 0; i < 3; i++) h[i] = sc.Int; long bi = 10000000000000; long ans = bi; ans = Math.Min(ans, count(h[1], h[0], h[2])); ans = Math.Min(ans, count(h[1], h[2], h[0])); ans = Math.Min(ans, count(h[0], h[2], h[1])); ans = Math.Min(ans, count(h[2], h[0], h[1])); if (ans == bi) sw.WriteLine("-1"); else sw.WriteLine(ans); sw.Flush(); } static long count(int sml, int mid, int big) { long bi = 10000000000000; if (d == 0) { if (sml < mid && mid < big) return 0; return bi; } long ret = 0; long s = sml, m = mid, b = big; if (b <= m) { long t = (m - b) / d + 1; m -= t * d; if (m <= 0) return bi; ret += t; } if (m <= s) { long t = (s - m) / d + 1; ret += t; } return ret; } static long pow(long a, long b) { if (b == 0) return 1; if (b == 1) return a % M; long t = pow(a, b / 2); if ((b & 1) == 0) return t * t % M; else return t * t % M * a % M; } } class Scan { public int Int { get { return int.Parse(Console.ReadLine().Trim()); } } public long Long { get { return long.Parse(Console.ReadLine().Trim()); } } public string Str { get { return Console.ReadLine().Trim(); } } public int[] IntArr { get { return Console.ReadLine().Trim().Split().Select(int.Parse).ToArray(); } } public int[] IntArrWithSep(char sep) { return Console.ReadLine().Trim().Split(sep).Select(int.Parse).ToArray(); } public long[] LongArr { get { return Console.ReadLine().Trim().Split().Select(long.Parse).ToArray(); } } public double[] DoubleArr { get { return Console.ReadLine().Split().Select(double.Parse).ToArray(); } } public string[] StrArr { get { return Console.ReadLine().Trim().Split(); } } public List IntList { get { return Console.ReadLine().Trim().Split().Select(int.Parse).ToList(); } } public List LongList { get { return Console.ReadLine().Trim().Split().Select(long.Parse).ToList(); } } public void Multi(out int a, out int b) { var arr = IntArr; a = arr[0]; b = arr[1]; } public void Multi(out int a, out int b, out int c) { var arr = IntArr; a = arr[0]; b = arr[1]; c = arr[2]; } public void Multi(out int a, out int b, out int c, out int d) { var arr = IntArr; a = arr[0]; b = arr[1]; c = arr[2]; d = arr[3]; } public void Multi(out int a, out string b) { var arr = StrArr; a = int.Parse(arr[0]); b = arr[1]; } public void Multi(out int a, out int b, out string c) { var arr = StrArr; a = int.Parse(arr[0]); b = int.Parse(arr[1]); c = arr[2]; } public void Multi(out int a, out char b) { var arr = StrArr; a = int.Parse(arr[0]); b = arr[1][0]; } public void Multi(out long a, out long b) { var arr = LongArr; a = arr[0]; b = arr[1]; } public void Multi(out long a, out int b) { var arr = LongArr; a = arr[0]; b = (int)arr[1]; } public void Multi(out string a, out string b) { var arr = StrArr; a = arr[0]; b = arr[1]; } } }