#include <iostream>
#include <array>
#include <algorithm>
#include <vector>
#include <bitset>
#include <set>
#include <unordered_set>
#include <cmath>
#include <complex>
#include <deque>
#include <iterator>
#include <numeric>
#include <map>
#include <unordered_map>
#include <queue>
#include <stack>
#include <string>
#include <tuple>
#include <utility>
#include <limits>
#include <iomanip>
#include <functional>
#include <cassert>
using namespace std;

using ll=long long;
template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;
using vll = V<ll>;
using vvll = V<vll>;
#define rep(i, k, n) for (ll i=k; i<(ll)n; ++i)
#define REP(i, n) rep(i, 0, n)
#define ALL(v) v.begin(),v.end()
template < class T > inline bool chmax(T& a, T b) {if (a < b) { a=b; return true; } return false; }
template < class T > inline bool chmin(T& a, T b) {if (a > b) { a=b; return true; } return false; }
#define DEBUG_VLL(vec) REP(sz, vec.size()) std::cerr<<vec[sz]<<(sz==vec.size()-1?'\n':' ');

const long long MOD = 1000000007;
const long long HIGHINF = (long long)1e18;
const int INF = (int)1e9;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n; cin >> n;
    V<int> a(n), b(n);
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n; i++) cin >> b[i];
    if (a == b) cout << 0 << '\n';
    else {
        int bcnt = 0, diff;
        for (int i = 0; i < n; i++) {
            if (a[i] < b[i]) {
                bcnt++;
                diff = b[i] - a[i];
            }
        }
        if (bcnt > 1) {
            cout << -1 << '\n';
            return 0;
        }
        for (int i = 0; i < n; i++) {
            if (a[i] < b[i]) a[i] = b[i];
            else a[i] -= diff;
        }

        bcnt = 0;
        for (int i = 0; i < n; i++) {
            if (a[i] == b[i]) bcnt++;
        }
        if (bcnt == n) {
            cout << diff << '\n';
            return 0;
        } else if (bcnt != 2) {
            cout << -1 << '\n';
            return 0;
        } else {
            int ab = INF;
            for (int i = 0; i < n; i++) {
                if (a[i] == b[i]) continue;
                if (ab == INF) ab = a[i] - b[i];
                else if (ab != a[i] - b[i]) {
                    cout << -1 << '\n';
                    return 0;
                }
            }
            if (ab < 0 || (ab & 1)) cout << -1 << '\n';
            else cout << diff + ab << '\n';
        }
    }
    return 0;
}