using System; using System.Collections.Generic; using System.Text; using System.Linq; class Program { public void Proc() { Reader.IsDebug = false; int target = int.Parse(Reader.ReadLine()); this.dic = new Dictionary[target + 1001]; for(int i=1000; i<=target; i+=1000) { this.GetAns(BeforeType.Other, i); } long ans = this.GetAns(BeforeType.Other, target); Console.WriteLine(ans); } Dictionary[] dic; private long GetAns(BeforeType before, int remain) { if(dic[remain] == null) { dic[remain] = new Dictionary(); } if(dic[remain].ContainsKey(before)) { return dic[remain][before]; } if(remain == 1) { if(before == BeforeType.KenKen) { return 1; } if(before == BeforeType.Pa) { return 1; } if(before == BeforeType.Other) { return 1; } return 2; } long ans = 0; if( before == BeforeType.Ken) { ans += this.GetAns(BeforeType.KenKen, remain - 1); } if(before == BeforeType.Ken || before == BeforeType.KenKen) { ans += this.GetAns(BeforeType.Pa, remain - 1); } if(before != BeforeType.Ken && before != BeforeType.KenKen) { ans += this.GetAns(BeforeType.Ken, remain - 1); } ans = ans % this.ModNum; dic[remain].Add(before, ans); return ans; } private long ModNum = 1000000000 + 7; public enum BeforeType { Ken, KenKen, Pa, Other } public class Reader { public static bool IsDebug = true; private static String PlainInput = @" 983039 "; private static System.IO.StringReader Sr = null; public static string ReadLine() { if (IsDebug) { if (Sr == null) { Sr = new System.IO.StringReader(PlainInput.Trim()); } return Sr.ReadLine(); } else { return Console.ReadLine(); } } } static void Main() { Program prg = new Program(); prg.Proc(); } }