#include <bits/stdc++.h>

using namespace std;

// #define LOCK_GETCHAR
// #define USE_INT_128

#if __cplusplus < 201400
#warning "Please use c++14 or higher."
#define CONSTEXPR_FUNC
#define ENABLE_IF_INT
#else
#define CONSTEXPR_FUNC constexpr
#define ENABLE_IF_INT , enable_if_t<_is_integer<T>, int> = 0
template <class T> constexpr bool _is_integer = numeric_limits<T>::is_integer;
template <> constexpr bool _is_integer<bool> = false;
template <> constexpr bool _is_integer<char> = false;
#ifdef USE_INT_128
template <> constexpr bool _is_integer<__int128> = true;
template <> constexpr bool _is_integer<__uint128_t> = true;
#endif
#endif

#if !defined(_WIN32) && !defined(__CYGWIN__) && !defined(LOCK_GETCHAR)
#define getchar getchar_unlocked
#endif

#define il inline
#define mkp make_pair
#define fi first
#define se second
#define ssz(x) (signed((x).size()))
#define _loop_i_t(j, k) make_signed_t<decltype((j) - (k))>
#define For(i, j, k) for (_loop_i_t(j, k) i = (j); i <= (k); ++i) // NOLINT
#define ForDown(i, j, k)                                                       \
  for (_loop_i_t(j, k) i = (j); i >= decltype(i)(k); --i) // NOLINT
#define eb emplace_back
#ifndef ONLINE_JUDGE
#define FileIO(filename)                                                       \
  freopen(filename ".in", "r", stdin);                                         \
  freopen(filename ".out", "w", stdout)
#else
#define FileIO(filename) void(0)
#endif

using ll = long long;
using uint = unsigned int;
using ull = unsigned long long;
using db = double;
using ldb = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#ifdef USE_INT_128
using lll = __int128_t;
using ulll = __uint128_t;
#endif

// clang-format off
CONSTEXPR_FUNC il ll qpow(ll x, ull y, ll mod){ ll ans = 1; x %= mod; while (y) { if (y & 1) (ans *= x) %= mod; (x *= x) %= mod; y >>= 1; } return ans; }
template<typename T> CONSTEXPR_FUNC il void cmin(T & x, const T &y){ x = min(x, y); }
template<typename T> CONSTEXPR_FUNC il void cmax(T & x, const T &y){ x = max(x, y); }
template<typename T ENABLE_IF_INT> il void read(T &x){ x = 0; int f = 1; int c = getchar(); while (!isdigit(c)) { if (c == '-') f = -1; c = getchar(); } while (isdigit(c)) { x = x * 10 + (c - '0'); c = getchar(); } x *= f; }
template<typename T, typename ... Args> il void read(T &x, Args &... y){ read(x), read(y...); }
// clang-format on

// File head end

namespace {
constexpr ll MAXN = 1e6 + 5;
int T, n, a[MAXN], b[MAXN];
ll f[MAXN][4];
il void Main() {
  read(T);
  while (T--) {
    read(n);
    For(i, 1, n) read(a[i]);
    For(i, 1, n) read(b[i]);
    bool ok = 1;
    memset(f, 0xc0, (n + 1) * 4 * sizeof(ll)), f[0][0] = 0;
    For(i, 1, n) {
      if (!a[i]) {
        if (!b[i]) {
          memcpy(f[i], f[i - 1], sizeof(f[i - 1]));
          continue;
        }
        puts("-1"), ok = 0;
        break;
      }
      if (b[i])
        For(C, -1, 1) For(B, 0, -C + 1) For(S, 0, 3) {
          int u = max(0, (S >> 1) - B - C), v = max(0, ((S & 1) + C));
          if (u > 1 || v > 1)
            continue;
          int T = u << 1 | v;
          cmax(f[i][T], f[i - 1][S] + B * (-a[i] + 1) + C * (b[i] - a[i]));
        }
      else
        For(A, 0, 1) For(S, 0, 3) {
          int u = max(0, (S >> 1) + A), v = max(0, ((S & 1) + 0));
          if (u > 1 || v > 1)
            continue;
          int T = u << 1 | v;
          cmax(f[i][T], f[i - 1][S] + A * a[i]);
        }
    }
    if (ok) {
      ll ans = max({f[n][0], f[n][1], f[n][2], f[n][3]});
      cout << ans << '\n';
    }
  }
}
} // namespace

signed main() { return Main(), 0; }