#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    int N;
    cin >> N;
    vector<ll> A(N), B(N);
    for (int i = 0; i < N; i++) cin >> A[i];
    for (int i = 0; i < N; i++) cin >> B[i];

    // 计算差分
    vector<ll> diff(N);
    ll pos = 0, neg = 0;
    for (int i = 0; i < N; i++) {
        diff[i] = B[i] - A[i];
        if (diff[i] > 0) pos += diff[i];
        else neg += -diff[i];
    }

    // 如果正负增量不相等，无法通过增减完成
    if (pos != neg) {
        cout << -1 << endl;
        return 0;
    }

    // 检查每个位置是否会降到负数
    ll cur = 0; // 当前累计的操作影响
    for (int i = 0; i < N; i++) {
        cur += diff[i]; // 累计到这个位置的操作影响
        if (A[i] + cur < 0) { // 操作过程中可能降到负数
            cout << -1 << endl;
            return 0;
        }
    }

    cout << pos << endl;
    return 0;
}