using System; using System.Collections.Generic; using System.Collections; using System.Collections.Specialized; using System.Linq; using System.Text; using System.IO; using System.Reflection; using static System.Math; using System.Numerics; using System.Threading; using System.Runtime.CompilerServices; using System.Diagnostics; //using nint=System.Int32; static class Program{ const int mod=10; static void Main(){ Sc sc=new Sc(); var s=sc.La; var g=new long[][]{ new long[]{0,1,0}, new long[]{0,0,1}, new long[]{1,1,1}, }; var b=new long[]{s[0],s[1],s[2]}; var c=Mp(b,g,s[3]-1); Console.WriteLine("{0}",c[0]); } static long[] Mp(long[] r,long[][] x,long e){ while(e>0){ if((e&1)>0){r=Mm(x,r);} x=Mm(x,x); e>>=1; } return r; } static long[] Mm(long[][] a,long[] b){ var q=new long[b.Length]; for(int j=0;j0){ if((e&1)>0){r=Mm(x,r);} x=Mm(x,x); e>>=1; } return r; } } public class Sc{ public int I{get{return int.Parse(Console.ReadLine());}} public long L{get{return long.Parse(Console.ReadLine());}} public double D{get{return double.Parse(Console.ReadLine());}} public string S{get{return Console.ReadLine();}} public int[] Ia{get{return Array.ConvertAll(Console.ReadLine().Split(),int.Parse);}} public long[] La{get{return Array.ConvertAll(Console.ReadLine().Split(),long.Parse);}} public double[] Da{get{return Array.ConvertAll(Console.ReadLine().Split(),double.Parse);}} public string[] Sa{get{return Console.ReadLine().Split();}} public object[] Oa{get{return Console.ReadLine().Split();}} public int[] Ia2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),int.Parse);}} public int[] Ia3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),int.Parse);} public int[] Ia3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),int.Parse);} public long[] La2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),long.Parse);}} public long[] La3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),long.Parse);} public long[] La3(int a){return Array.ConvertAll((Console.ReadLine()+" "+a.ToString()).Split(),long.Parse);} public double[] Da2{get{return Array.ConvertAll(("0 "+Console.ReadLine()+" 0").Split(),double.Parse);}} public double[] Da3(string a,string b){return Array.ConvertAll((a+Console.ReadLine()+b).Split(),double.Parse);} public T[] Arr(int n,Func f){var a=new T[n];for(int i=0;i(int n,Func f){var a=new T[n];for(int i=0;i(int n,Func f){var a=new T[n];for(int i=0;i(int n,Func f){var a=new T[n];for(int i=0;i(){var s=Console.ReadLine().Split();return (Ct(s[0]),Ct(s[1]));} public (T,T,T) Tp3(){var s=Console.ReadLine().Split();return (Ct(s[0]),Ct(s[1]),Ct(s[2]));} public (T,T,T,T) Tp4(){var s=Console.ReadLine().Split();return (Ct(s[0]),Ct(s[1]),Ct(s[2]),Ct(s[3]));} public (T1,T2) Tp2(){var s=Console.ReadLine().Split();return (Ct(s[0]),Ct(s[1]));} public (T1,T1,T2) Tp3(){var s=Console.ReadLine().Split();return (Ct(s[0]),Ct(s[1]),Ct(s[2]));} private T Ct(string s){return (T)Convert.ChangeType(s,typeof(T));} }