//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2")
#pragma GCC optimize("Ofast","unroll-loops","inline")
#include<bits/stdc++.h>
#define ll long long
#define int ll
#define pb push_back
#define pii pair<int,int>
#define MP make_pair
#define fi first
#define se second
using namespace std;
const int N=1e6+20,M=1e6+20,mod=998244353;
const int Inf=1e18;
int n,a[N],b[N],f[N][2][2];
void solve(){
	cin>>n;
	for(int i=1;i<=n;i++) cin>>a[i];
	for(int i=1;i<=n;i++) cin>>b[i];
	for(int i=1;i<=n;i++) if(!a[i]&&b[i]) return cout<<-1<<'\n',void();
	for(int i=1;i<=n;i++) for(int j=0;j<2;j++) for(int k=0;k<2;k++) f[i][j][k]=-Inf;
	f[0][0][0]=0;
	for(int i=1;i<=n;i++){
		if(b[i]){
			int w1=(-a[i]+1),w2=(b[i]-a[i]);
			for(int j=0;j<2;j++) for(int k=0;k<2;k++) if(f[i-1][j][k]!=-Inf) for(int B=-1;B<2;B++) for(int A=0;A<=2;A++){
				int nj=max(0ll,j-A-B),nk=max(0ll,k+B);
				if(nj<2&&nk<2) f[i][nj][nk]=max(f[i][nj][nk],f[i-1][j][k]+A*w1+B*w2);
			}
		}
		else{
			int W=a[i];
			for(int j=0;j<2;j++) for(int k=0;k<2;k++) if(f[i-1][j][k]!=-Inf) for(int D=0;D<2;D++){
				int nj=max(0ll,j+D),nk=max(0ll,k);
				if(nj<2&&nk<2) f[i][nj][nk]=max(f[i][nj][nk],f[i-1][j][k]+D*W);
			}
		}
	}
	int ans=0;
	for(int j=0;j<2;j++) for(int k=0;k<2;k++) ans=max(ans,f[n][j][k]);
	cout<<ans<<'\n';
}
signed main(){
//	freopen("game.in","r",stdin);
//	freopen("game.out","w",stdout);
	ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	int T;cin>>T;
	while(T--) solve();
	return 0;
}