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;
using nint=System.Int32;
static class Program{
	const long inf=long.MaxValue>>1;
	const int mod=998244353;
	static Sc sc=new Sc();
	static void Main(){
		Pt pt=new Pt(Solve);
		pt.Sm();
	}
	static void Solve(Pt pt) {
		var n=sc.I;
		var a=sc.Ia;
		var avl=new Avl();
		avl.Ud(0);
		for(int i = 0;i < n;i++) {
			var lid=new List<int>();
			var liu=new List<int>();
			avl.En(e=>{
				if(avl.Hs(a[i]+e.n)) {lid.Add(a[i]+e.n);}
				else {liu.Add(a[i]+e.n);}
			});
			for(int j = 0;j < lid.Count;j++) {avl.Dl(lid[j]);}
			for(int j = 0;j < liu.Count;j++) {avl.Ud(liu[j]);}
		}
		int ans=0;
		avl.En(e=>{ans^=e.n;});
		pt.Wl(ans);
	}
}
public class Avl{
	public class Nd{
		public int h=1,c=1;
		public readonly nint n;
		public Nd l,r;
		public Nd(nint n,Nd du){this.n=n;l=du;r=du;}
	}
	public Nd root,du;
	public int cnt=0;
	public Avl(){
		du=new Nd(nint.MinValue,du);du.h=0;du.c=0;
		root=du;
	}
	public Avl(Avl z){
		du=new Nd(nint.MinValue,du);du.h=0;du.c=0;
		root=Fu(z.root);
		cnt=z.cnt;
		Nd Fu(Nd nd){
			if(nd.h==0){return du;}
			Nd mn=new Nd(nd.n,du);
			mn.h=nd.h;
			mn.c=nd.c;
			mn.l=Fu(nd.l);
			mn.r=Fu(nd.r);
			return mn;
		}
	}
	public void Ud(nint n){
		Nd mn=new Nd(n,du);
		if(root==du){root=mn;}
		else{
			Fu(root,mn);
			if(Abs(root.l.h-root.r.h)>1){root=Rotate(root);}
		}
		cnt++;
	}
	private void Fu(Nd t,Nd mn){
		t.c++;
		if(t.n>mn.n){
			if(t.l!=du){
				Fu(t.l,mn);
				if(Abs(t.l.l.h-t.l.r.h)>1){t.l=Rotate(t.l);}
			}
			else{t.l=mn;}
		}
		else{
			if(t.r!=du){
				Fu(t.r,mn);
				if(Abs(t.r.l.h-t.r.r.h)>1){t.r=Rotate(t.r);}
			}
			else{t.r=mn;}
		}
		t.h=Max(t.l.h,t.r.h)+1;
	}
	private Nd Rotate(Nd t){
		Nd nd=du;
		if(t.l.h>t.r.h){
			if(t.l.l.h>t.l.r.h){
				nd=t.l;t.l=t.l.r;nd.r=t;
				t.h=Max(t.l.h,t.r.h)+1;
				t.c=t.l.c+t.r.c+1;
			}
			else{
				nd=t.l.r;
				t.l.r=nd.l;nd.l=t.l;
				t.l.h=Max(t.l.l.h,t.l.r.h)+1;
				t.l.c=t.l.l.c+t.l.r.c+1;
				t.l=nd.r;nd.r=t;
				t.h=Max(t.l.h,t.r.h)+1;
				t.c=t.l.c+t.r.c+1;
			}
		}
		else{
			if(t.r.l.h>t.r.r.h){
				nd=t.r.l;
				t.r.l=nd.r;nd.r=t.r;
				t.r.h=Max(t.r.l.h,t.r.r.h)+1;
				t.r.c=t.r.l.c+t.r.r.c+1;
				t.r=nd.l;nd.l=t;
				t.h=Max(t.l.h,t.r.h)+1;
				t.c=t.l.c+t.r.c+1;
			}
			else{
				nd=t.r;t.r=t.r.l;nd.l=t;
				t.h=Max(t.l.h,t.r.h)+1;
				t.c=t.l.c+t.r.c+1;
			}
		}
		nd.h=Max(nd.l.h,nd.r.h)+1;
		nd.c=nd.l.c+nd.r.c+1;
		return nd;
	}
	public bool Dl(nint n){
		if(cnt==0){return false;}
		Nd t=root;
		if(t.n==n){
			root=Fd2(root);
			if(cnt==0){return true;}
			else if(Abs(root.l.h-root.r.h)>1){root=Rotate(root);}
			else{
				root.h=Max(root.l.h,root.r.h)+1;
				root.c=root.l.c+root.r.c+1;
			}
			return true;
		}
		bool bo=Fd1(root,n);
		if(Abs(root.l.h-root.r.h)>1){root=Rotate(root);}
		else{
			root.h=Max(root.l.h,root.r.h)+1;
			root.c=root.l.c+root.r.c+1;
		}
		return bo;
	}
	private bool Fd1(Nd t,nint n){
		if(t.n>n){
			if(t.l==du){return false;}
			else if(t.l.n!=n){
				bool bo=Fd1(t.l,n);
				if(Abs(t.l.l.h-t.l.r.h)>1){t.l=Rotate(t.l);}
				else{
					t.l.h=Max(t.l.l.h,t.l.r.h)+1;
					t.l.c=t.l.l.c+t.l.r.c+1;
				}
				return bo;
			}
			else{
				t.l=Fd2(t.l);
				t.h=Max(t.l.h,t.r.h)+1;
				t.c=t.l.c+t.r.c+1;
				return true;
			}
		}
		else{
			if(t.r==du){return false;}
			else if(t.r.n!=n){
				bool bo=Fd1(t.r,n);
				if(Abs(t.r.l.h-t.r.r.h)>1){t.r=Rotate(t.r);}
				else{
					t.r.h=Max(t.r.l.h,t.r.r.h)+1;
					t.r.c=t.r.l.c+t.r.r.c+1;
				}
				return bo;
			}
			else{
				t.r=Fd2(t.r);
				t.h=Max(t.l.h,t.r.h)+1;
				t.c=t.l.c+t.r.c+1;
				return true;
			}
		}
	}
	private Nd Fd2(Nd dn){
		cnt--;
		if(dn.l==du){return dn.r;}
		if(dn.r==du){return dn.l;}
		Nd u=dn.l;
		if(u.r==du){
			u.r=dn.r;
			u.h=Max(u.l.h,u.r.h)+1;
			u.c=u.l.c+u.r.c+1;
			return u;
		}
		u=Fd3(u,dn);
		if(Abs(dn.l.l.h-dn.l.r.h)>1){u.l=Rotate(dn.l);}
		else{
			dn.l.h=Max(dn.l.l.h,dn.l.r.h)+1;
			dn.l.c=dn.l.l.c+dn.l.r.c+1;
		}
		u.h=Max(u.l.h,u.r.h)+1;
		u.c=u.l.c+u.r.c+1;
		return u;
	}
	private Nd Fd3(Nd u,Nd dn){
		if(u.r.r!=du){
			Nd v=Fd3(u.r,dn);
			if(Abs(u.r.l.h-u.r.r.h)>1){u.r=Rotate(u.r);}
			else{
				u.r.h=Max(u.r.l.h,u.r.r.h)+1;
				u.r.c=u.r.l.c+u.r.r.c+1;
			}
			return v;
		}
		else{
			Nd v=u.r;u.r=u.r.l;v.l=dn.l;v.r=dn.r;
			return v;
		}
	}
	public bool Hs(nint n){
		Nd t=root;
		if(cnt==0){return false;}
		if(t.n==n){return true;}
		bool bo=false;
		while(true){
			if(t.n>n){
				if(t.l==du){break;}
				else if(t.l.n!=n){t=t.l;}
				else{bo=true;break;}
			}
			else{
				if(t.r==du){break;}
				else if(t.r.n!=n){t=t.r;}
				else{bo=true;break;}
			}
		}
		return bo;
	}
	public Nd Ra(int n){return cnt>=n&&cnt!=0?Fr(root,n):null;}
	private Nd Fr(Nd t,int n){
		if(t.l.c>n-1){return Fr(t.l,n);}
		if(t.l.c<n-1){return Fr(t.r,n-t.l.c-1);}
		return t;
	}
	public Nd Lb(nint n){return cnt!=0?Flb(root,n):null;}
	private Nd Flb(Nd t,nint n){
		if(t.n<n){
			if(t.r==du){return null;}
			return Flb(t.r,n);
		}
		if(t.n>n){
			if(t.l==du){return t;}
			Nd u=Flb(t.l,n);
			return u==null?t:u;
		}
		return t;
	}
	public Nd Ub(nint n){return cnt!=0?Fub(root,n):null;}
	private Nd Fub(Nd t,nint n){
		if(t.n>n){
			if(t.l==du){return null;}
			return Fub(t.l,n);
		}
		if(t.n<n){
			if(t.r==du){return t;}
			Nd u=Fub(t.r,n);
			return u==null?t:u;
		}
		return t;
	}
	public int Rg(nint a,nint b){return cnt!=0?Frg(root,a,b,false,false):0;}
	private int Frg(Nd t,nint a,nint b,bool l,bool r){
		if(t.h==0){return 0;}
		if(l&&r){return t.c;}
		if(t.n<a){return Frg(t.r,a,b,t.n>=a,r);}
		if(t.n>b){return Frg(t.l,a,b,l,t.n<=b);}
		return Frg(t.l,a,b,l,t.n<=b)+Frg(t.r,a,b,t.n>=a,r)+1;
	}
	public void En(Action<Nd> f){if(cnt>0){Fen(root,f);}}
	private void Fen(Nd t,Action<Nd> f){
		if(t.r!=du){Fen(t.r,f);}
		f(t);
		if(t.l!=du){Fen(t.l,f);}
	}
	public void En(nint l,nint r,Action<Nd> f){if(cnt>0){Fen(root,l,r,false,false,f);}}
	private void Fen(Nd t,nint a,nint b,bool l,bool r,Action<Nd> f){
		if(l&&r){
			if(t.l!=du){Fen(t.l,f);}
			f(t);
			if(t.r!=du){Fen(t.r,f);}
		}
		else{
			if(t.n<a){if(t.r!=du){Fen(t.r,a,b,l,r,f);}}
			else if(t.n>b){if(t.l!=du){Fen(t.l,a,b,l,r,f);}}
			else{
				if(t.l!=du){Fen(t.l,a,b,l,t.n<=b,f);}
				f(t);
				if(t.r!=du){Fen(t.r,a,b,t.n>=a,r,f);}
			}
		}
	}
	public void Enl(nint l,Func<Nd,bool> f){if(cnt>0){Fenl(root,l,f);}}
	private bool Fenl(Nd t,nint a,Func<Nd,bool> f){
		bool bo=true;
		if(t.n<a){
			if(t.r!=du){bo&=Fenl(t.r,a,f);}
		}
		else{
			if(t.l!=du){bo&=Fenl(t.l,a,f);}
			if(bo){bo&=f(t);}
			if(bo&&t.r!=du){bo&=Fenl(t.r,a,f);}
		}
		return bo;
	}
	public void Enr(nint r,Func<Nd,bool> f){if(cnt>0){Fenr(root,r,f);}}
	private bool Fenr(Nd t,nint b,Func<Nd,bool> f){
		bool bo=true;
		if(t.n>b){
			if(t.l!=du){bo&=Fenr(t.l,b,f);}
		}
		else{
			if(t.r!=du){bo&=Fenr(t.r,b,f);}
			if(bo){bo&=f(t);}
			if(bo&&t.l!=du){bo&=Fenr(t.l,b,f);}
		}
		return bo;
	}
}
public class Pt{
	private StringBuilder sb=new StringBuilder();
	public Pt(Action<Pt> 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(char 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(char 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<T>(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<T>(int n,Func<T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f();}return a;}
	public T[] Arr<T>(int n,Func<int,T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i);}return a;}
	public T[] Arr<T>(int n,Func<string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(Sp(Rl()));}return a;}
	public T[] Arr<T>(int n,Func<int,string[],T> f){var a=new T[n];for(int i=0;i<n;i++){a[i]=f(i,Sp(Rl()));}return a;}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T) Tp2<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T) Tp3<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T,T) Tp4<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]),Ct<T>(s[3]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T,T,T) Tp5<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]),Ct<T>(s[3]),Ct<T>(s[4]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T,T,T,T,T,T) Tp6<T>(){var s=Sp(Rl());return (Ct<T>(s[0]),Ct<T>(s[1]),Ct<T>(s[2]),Ct<T>(s[3]),Ct<T>(s[4]),Ct<T>(s[5]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T1,T2) Tp2<T1,T2>(){var s=Sp(Rl());return (Ct<T1>(s[0]),Ct<T2>(s[1]));}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	public (T1,T1,T2) Tp3<T1,T2>(){var s=Sp(Rl());return (Ct<T1>(s[0]),Ct<T1>(s[1]),Ct<T2>(s[2]));}
}
public class Scr:Sc{
	private List<string> li=new List<string>();
	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<string> li=new List<string>();
	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));}
}