#ifdef LOCAL
#include "stdafx.h"
#else
#include <bits/stdc++.h>
#define IL inline
#define LL long long
#define eb emplace_back
#define sz(v) ((int) (v).size())
#define me(f, x) memset(f, x, sizeof(f))
#define mc(f, g) memcpy(f, g, sizeof(g))
#define L(i, j, k) for (int i = (j); i <= (k); ++i)
#define R(i, j, k) for (int i = (j); i >= (k); --i)
#define FIO(FILE) freopen(FILE".in", "r", stdin), freopen(FILE".out", "w", stdout)
using namespace std;

using vi = vector<int>;
#endif

constexpr int N = 1e6 + 9;
int n, a[N], b[N];
LL dp[1 << 2], _dp[1 << 2];

void slv () {
  cin >> n;
  L (i, 1, n) {
    cin >> a[i];
  }
  L (i, 1, n) {
    cin >> b[i];
  }
  L (i, 1, n) {
    if (!a[i] && b[i]) {
      cout << "-1\n";
      return;
    }
  }
  me(dp, -0x3f);
  dp[0] = 0;
  L (i, 1, n) {
    me(_dp, -0x3f);
    L (B, -1, 1) {
      if (!b[i] && B != 0) {
        continue;
      }
      L (A, B - 1, B + 1) {
        if ((!b[i] && A >= 0) || (b[i] && A <= 0)) {
          LL w = B * (b[i] - a[i]) + A * (a[i] - (b[i] > 0));
          L (S, 0, 3) {
            int T = 0;
            bool fl = true;
            L (j, 0, 1) {
              int x = max(0, (S >> j & 1) + (j ? B : A - B));
              if (x > 1) {
                fl = false;
                break;
              } else {
                T |= x << j;
              }
            }
            if (fl) {
              _dp[T] = max(_dp[T], dp[S] + w);
            }
          }
        }
      }
    }
    mc(dp, _dp);
  }
  cout << *max_element(dp, dp + 4) << '\n';
}

int main () {
  ios::sync_with_stdio(0), cin.tie(0);
  int T;
  cin >> T;
  while (T--) {
    slv();
  }
}
// I love WHQ!