using System; using System.Collections.Generic; using System.Collections; using System.Collections.Specialized; using System.Linq; using System.Text; using System.Text.RegularExpressions; using System.IO; using System.Reflection; using static System.Math; using System.Numerics; using System.Threading; using System.Runtime.CompilerServices; using System.Diagnostics; static class Program{ const long inf=long.MaxValue>>1; const int mod=(int)1e9+7; static Sc sc=new Sc(); static void Main(){ Pt pt=new Pt(Solve); pt.Sm(); } static void Solve(Pt pt) { int n=sc.I,m=n-1; var li=new List<(int v,int d)>[n+1]; var b=new bool[n+1]; var dt=new Dt[n+1]; for(int i=1;i<=n;i++){ li[i]=new List<(int,int)>(); dt[i]=new Dt(1); } for(int i=0;i0){ long t=a/b; a-=t*b;(a,b)=(b,a); u-=t*v;(u,v)=(v,u); } u%=mod; if(u<0){u+=mod;} return u%mod; } } public class Dt{ public int n; public int[] h; const int m=31,mod=(int)1e9+7; public Dt(int z){ n=z; h=Enumerable.Repeat(z,m).ToArray(); } public Dt(Dt d){ n=d.n; h=new int[m]; Array.Copy(d.h,h,m); } public void Add(Dt d,int c) { n+=d.n; for(int i = 0;i < m;i++) { if(((1< f){f(this);} public void W(int s){sb.Append(s);} public void W(long s){sb.Append(s);} public void W(double s){sb.Append(s);} public void W(decimal s){sb.Append(s);} public void W(string s){sb.Append(s);} public void W(object s){sb.Append(s);} public void W(string f,int s){sb.Append(s.ToString(f));} public void W(string f,long s){sb.Append(s.ToString(f));} public void W(string f,double s){sb.Append(s.ToString(f));} public void W(string f,decimal s){sb.Append(s.ToString(f));} public void Wl(int s){sb.Append(s).Append(Environment.NewLine);} public void Wl(long s){sb.Append(s).Append(Environment.NewLine);} public void Wl(double s){sb.Append(s).Append(Environment.NewLine);} public void Wl(decimal s){sb.Append(s).Append(Environment.NewLine);} public void Wl(string s){sb.Append(s).Append(Environment.NewLine);} public void Wl(object s){sb.Append(s).Append(Environment.NewLine);} public void Wl(string f,int s){sb.Append(s.ToString(f)).Append(Environment.NewLine);} public void Wl(string f,long s){sb.Append(s.ToString(f)).Append(Environment.NewLine);} public void Wl(string f,double s){sb.Append(s.ToString(f)).Append(Environment.NewLine);} public void Wl(string f,decimal s){sb.Append(s.ToString(f)).Append(Environment.NewLine);} public void Wl(int[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);} public void Wl(long[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);} public void Wl(double[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);} public void Wl(string[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);} public void Wl(object[] s){sb.Append(string.Join(" ",s)).Append(Environment.NewLine);} public void Wl(){sb.Append(Environment.NewLine);} public void Sm(){Console.Write(sb);} public static bool operator==(Pt a,Pt b){return a.sb.ToString()==b.sb.ToString();} public static bool operator!=(Pt a,Pt b){return a.sb.ToString()!=b.sb.ToString();} public override bool Equals(object obj){return false;} public override int GetHashCode(){return 0;} } public class Sc{ [MethodImpl(MethodImplOptions.AggressiveInlining)] protected virtual string Rl(){return Console.ReadLine();} [MethodImpl(MethodImplOptions.AggressiveInlining)] protected virtual string[] Sp(string st){return st.Split();} [MethodImpl(MethodImplOptions.AggressiveInlining)] private T Ct(string s){return (T)Convert.ChangeType(s,typeof(T));} public virtual int I{get{return int.Parse(Rl());}} public virtual long L{get{return long.Parse(Rl());}} public virtual double D{get{return double.Parse(Rl());}} public virtual string S{get{return Rl();}} public int[] Ia{get{return Array.ConvertAll(Sp(Rl()),int.Parse);}} public long[] La{get{return Array.ConvertAll(Sp(Rl()),long.Parse);}} public double[] Da{get{return Array.ConvertAll(Sp(Rl()),double.Parse);}} public string[] Sa{get{return Sp(Rl());}} public object[] Oa{get{return Sp(Rl());}} public int[] Ia2{get{return Array.ConvertAll(Sp("0 "+Rl()+" 0"),int.Parse);}} public int[] Ia3(string a,string b){return Array.ConvertAll(Sp(a+Rl()+b),int.Parse);} public int[] Ia3(int a){return Array.ConvertAll(Sp(Rl()+" "+a.ToString()),int.Parse);} public long[] La2{get{return Array.ConvertAll(Sp("0 "+Rl()+" 0"),long.Parse);}} public long[] La3(string a,string b){return Array.ConvertAll(Sp(a+Rl()+b),long.Parse);} public long[] La3(int a){return Array.ConvertAll(Sp(Rl()+" "+a.ToString()),long.Parse);} public double[] Da2{get{return Array.ConvertAll(Sp("0 "+Rl()+" 0"),double.Parse);}} public double[] Da3(string a,string b){return Array.ConvertAll(Sp(a+Rl()+b),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=Sp(Rl());return (Ct(s[0]),Ct(s[1]));} [MethodImpl(MethodImplOptions.AggressiveInlining)] public (T,T,T) Tp3(){var s=Sp(Rl());return (Ct(s[0]),Ct(s[1]),Ct(s[2]));} [MethodImpl(MethodImplOptions.AggressiveInlining)] public (T,T,T,T) Tp4(){var s=Sp(Rl());return (Ct(s[0]),Ct(s[1]),Ct(s[2]),Ct(s[3]));} [MethodImpl(MethodImplOptions.AggressiveInlining)] public (T,T,T,T,T) Tp5(){var s=Sp(Rl());return (Ct(s[0]),Ct(s[1]),Ct(s[2]),Ct(s[3]),Ct(s[4]));} [MethodImpl(MethodImplOptions.AggressiveInlining)] public (T,T,T,T,T,T) Tp6(){var s=Sp(Rl());return (Ct(s[0]),Ct(s[1]),Ct(s[2]),Ct(s[3]),Ct(s[4]),Ct(s[5]));} [MethodImpl(MethodImplOptions.AggressiveInlining)] public (T1,T2) Tp2(){var s=Sp(Rl());return (Ct(s[0]),Ct(s[1]));} [MethodImpl(MethodImplOptions.AggressiveInlining)] public (T1,T1,T2) Tp3(){var s=Sp(Rl());return (Ct(s[0]),Ct(s[1]),Ct(s[2]));} } public class Scr:Sc{ private List li=new List(); private int l=0; private bool bo=false; [MethodImpl(MethodImplOptions.AggressiveInlining)] protected override string Rl(){ if(bo){return li[l++%li.Count];} li.Add(Console.ReadLine()); return li[li.Count-1]; } public void Again(){bo=true;} } public class Sc2:Sc{ private string[] sps=new string[]{" "," ","\t"}; [MethodImpl(MethodImplOptions.AggressiveInlining)] protected override string[] Sp(string st){return st.Split(sps,StringSplitOptions.RemoveEmptyEntries);} public override int I{get{return int.Parse(Sp(Rl())[0]);}} public override long L{get{return long.Parse(Sp(Rl())[0]);}} public override double D{get{return double.Parse(Sp(Rl())[0]);}} public override string S{get{return Sp(Rl())[0];}} } public class Sct:Sc{ private List li=new List(); private int l=0; public void Add(int s){li.Add(s.ToString());} public void Add(long s){li.Add(s.ToString());} public void Add(double s){li.Add(s.ToString());} public void Add(string s){li.Add(s.ToString());} public void Add(object s){li.Add(s.ToString());} public void Add(int[] s){li.Add(string.Join(" ",s));} public void Add(long[] s){li.Add(string.Join(" ",s));} public void Add(double[] s){li.Add(string.Join(" ",s));} public void Add(string[] s){li.Add(string.Join(" ",s));} public void Add(object[] s){li.Add(string.Join(" ",s));} protected override string Rl(){return li[l++];} public void Clear(){li.Clear();l=0;} public void Again(){l=0;} public void Pf(){Console.WriteLine(string.Join("\n",li));} }