Problem:
Score : 1000 points

Problem Statement

There is a sequence of length N: a = (a_1, a_2, ..., a_N).
Here, each a_i is a non-negative integer.

Snuke can repeatedly perform the following operation:

Let the XOR of all the elements in a be x. Select an integer i (1 ≤ i ≤ N) and replace a_i with x.

Snuke's objective is to match a with another sequence b = (b_1, b_2, ..., b_N).
Here, each b_i is a non-negative integer.

Determine whether the objective is achievable, and find the minimum necessary number of operations if the answer is positive.

Constraints

2 ≤ N ≤ 10^5

a_i and b_i are integers.

0 ≤ a_i, b_i < 2^{30}

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N
b_1 b_2 ... b_N

Output

If the objective is achievable, print the minimum necessary number of operations.
Otherwise, print -1 instead.

Sample Input 1

3
0 1 2
3 1 0

Sample Output 1

2

At first, the XOR of all the elements of a is 3.
If we replace a_1 with 3, a becomes (3, 1, 2).

Now, the XOR of all the elements of a is 0.
If we replace a_3 with 0, a becomes (3, 1, 0), which matches b.

Sample Input 2

3
0 1 2
0 1 2

Sample Output 2

0

Sample Input 3

2
1 1
0 0

Sample Output 3

-1

Sample Input 4

4
0 1 2 3
1 0 3 2

Sample Output 4

5

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using System.Globalization;
using System.Diagnostics;
using System.Threading.Tasks;



class Myon
{
    public Myon() { }
    public static int Main()
    {
        new Myon().calc();
        return 0;
    }

    Scanner cin;


    void calc()
    {
        cin = new Scanner();
        int N = cin.nextInt();
        int[] A = cin.ArrayInt(N);
        int[] B = cin.ArrayInt(N);

        int[] a = new int[N + 1];
        int[] b = new int[N + 1];
        int xa = 0, xb = 0;
        for (int i = 0; i < N; i++)
        {
            xa ^= A[i]; xb ^= B[i];
        }
        a[N] = xa;  b[N] = xb;

        List<int> la = new List<int>(A);
        List<int> lb = new List<int>(B);
        la.Add(xa);
        lb.Add(xb);
        la.Sort(); lb.Sort();
        for (int i = 0; i < la.Count; i++)
        {
            if(la[i] != lb[i])
            {
                Console.WriteLine("-1");
                return;
            }
        }


        int nokori = 0;
        bool[] ok = new bool[N];
        Dictionary<int, List<int>> need = new Dictionary<int, List<int>>();
        for (int i = 0; i < N; i++)
        {
            if (A[i] == B[i])
            {
                ok[i] = true;
                continue;
            }
            if (!need.ContainsKey(B[i])) need[B[i]] = new List<int>();
            need[B[i]].Add(i);
            nokori++;
        }

        int ans = 0;
        int lastOKpos = 0;

        int tmp = xa;

        while (nokori > 0)
        {
            //for (int i = 0; i < N; i++)
            //{
            //    Console.Write(A[i] + " ");
            //}
            //Console.WriteLine();
            if(need.ContainsKey(tmp) && need[tmp].Count >= 1)
            {
                int ftmp = tmp;
                int pos = need[ftmp][need[ftmp].Count - 1];
                int nextX = A[pos];
                A[pos] = tmp;
                tmp = nextX;
                ok[pos] = true;

                ans++;
                nokori--;
                need[ftmp].RemoveAt(need[ftmp].Count - 1);
            }
            else
            {
                for (;lastOKpos < N; lastOKpos++)
                {
                    if (ok[lastOKpos]) continue;
                    if (A[lastOKpos] == tmp) continue;

                    int pos = lastOKpos;
                    int ftmp = tmp;
                    int nextX = A[pos];
                    A[pos] = tmp;
                    tmp = nextX;

                    ans++;
                    break;
                }
                if (lastOKpos == N) lastOKpos = 0;
            }
        }
        Console.WriteLine(ans);
    }

}



class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        if (s.Length == 0) return next();
        i = 0;
        return s[i++];
    }

    public int nextInt()
    {
        return int.Parse(next());
    }
    public int[] ArrayInt(int N, int add = 0)
    {
        int[] Array = new int[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextInt() + add;
        }
        return Array;
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public long[] ArrayLong(int N, long add = 0)
    {
        long[] Array = new long[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextLong() + add;
        }
        return Array;
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }


    public double[] ArrayDouble(int N, double add = 0)
    {
        double[] Array = new double[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextDouble() + add;
        }
        return Array;
    }
}