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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <cstdio>
#include <map>
#include <set>
#include <queue>
#include <vector>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#define rep(i,a,b) for(int i = a; i <= b; i++)
#define dep(i,a,b) for(int i = a; i >= b; i--) 
#define Rep(i,a) for(int i = 0; i < a; i++)
#define pb(a) push_back(a)
#define mp(a,b) make_pair(a,b)
#define ab(x) ((x) < 0 ? -(x) : (x))
using namespace std;
typedef long long LL;
typedef map<int, int>::iterator mit;
typedef set<int>::iterator sit;
typedef pair<int, int> pii;
#define x first
#define y second
const int N = 1e5 + 10;
int n, a[N], b[N], c[N], d[N], p[N], l;
map<int, int> val;
int f[N];
inline int find(int x) { return x == f[x] ? x : f[x] = find(f[x]); }
void merge(int a, int b) {
	a = find(a), b = find(b);
	if (a != b) f[a] = b;
}
int main() {
	scanf("%d",&n);
	rep(i,1,n) scanf("%d",a + i);
	rep(i,1,n) scanf("%d",b + i);
	a[n + 1] = 0; rep(i,1,n) a[n + 1] ^= a[i];
	b[n + 1] = 0; rep(i,1,n) b[n + 1] ^= b[i];
	n++;
	memcpy(c + 1, a + 1, n * sizeof(a[0]));
	memcpy(d + 1, b + 1, n * sizeof(b[0]));
	sort(c + 1, c + n + 1); sort(d + 1, d + n + 1);
	rep(i,1,n) if (c[i] != d[i]) { printf("-1\n"); return 0; }
	l = unique(c + 1, c + n + 1) - c - 1;
	rep(i,1,l) val[c[i]] = i;
	rep(i,1,n) a[i] = val[a[i]], b[i] = val[b[i]];
	static vector<int> pos[N];
	rep(i,1,n) pos[b[i]].pb(i);
	static bool vs[N];
	rep(i,1,n) {
		if (a[i] == b[i]) p[i] = i, vs[i] = true;
		else {
			while (vs[*pos[a[i]].rbegin()]) pos[a[i]].pop_back();
			p[i] = *pos[a[i]].rbegin();
			pos[a[i]].pop_back();
		}
	}
	rep(i,1,n) f[i] = i; static bool vis[N];

	rep(i,1,n) if (!vis[i]) {
		vis[i] = true;
		for(int j = p[i]; j != i; j = p[j]) vis[j] = true, merge(j, i);
	}
	rep(i,1,n) pos[a[i]].pb(i);
	rep(i,1,n) if (pos[i].size()) {
		int len = pos[i].size(), t = 0;
		rep(j,1,len - 1) {
			int x = pos[i][j];
			if (p[x] != x) {
				if (!t) t = x; else merge(t, x);
			}
		}
	}
	static int cnt[N];
	rep(i,1,n) cnt[find(i)]++;
	int ans = 0;
	rep(i,1,n) if (f[i] == i) {
		if (i == find(n)) ans += cnt[i] - 1;
		else if (cnt[i] > 1) ans += cnt[i] + 1;
	}
	printf("%d\n",ans);
	return 0;
}