#include<bits/stdc++.h>
#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 ll long long 
#define vi vector < int > 
#define sz(a) ((int) (a).size())
#define ll long long 
#define ull unsigned long long
#define me(a, x) memset(a, x, sizeof(a)) 
using namespace std;
const int N = 1 << 20;
int n;
int a[N], b[N];
ll dp[1 << 2], ndp[1 << 2];
void Main() {
	cin >> n;
	L(i, 1, n) {
		cin >> a[i];
	}
	L(i, 1, n) {
		cin >> b[i];
	}
	me(dp, -0x3f);
	dp[0] = 0;
	L(i, 1, n) {
		if(!a[i]) {
			if(b[i]) {
				cout << "-1\n";
				return ;
			}
			continue;
		}
		me(ndp, -0x3f);
		L(s, -1, 1) {
			if(b[i] == 0 && s != 0) continue;
			L(w, s - 1, s + 1) if((b[i] > 0 && w <= 0) || (!b[i] && w >= 0)) {
				ll add = (b[i] - a[i]) * s;
				if(b[i] == 0) add += a[i] * w;
				else add += (a[i] - 1) * w;
				
				int v[2] = {w - s, s};
				L(S, 0, (1 << 2) - 1) {
					int ok = 1, go = 0;
					L(j, 0, 1) {
						int SUM = max((S >> j & 1) + v[j], 0);
						if(SUM > 1) {
							ok = 0;
						} else if(SUM) {
							go |= 1 << j;
						}
					}
					if(ok) {
						ndp[go] = max(ndp[go], dp[S] + add);
					}
				}
			}
		}
		swap(dp, ndp);
	}
	cout << *max_element(dp, dp + 4) << '\n';
}
int main() {
	ios :: sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	int t; cin >> t; while(t--) Main();
	return 0;
}