296329512

#include<bits/stdc++.h>
using namespace std;
#define FELIX
#define ll long long int
#define vi vector<ll>
#define ip(v,n) for(ll i=0;i<n;i++)cin>>v[i];
#define op(v,n) for(ll i=0;i<n;i++)cout<<v[i]<<" ";
#define opp(v,n) for(ll i=0;i<n;i++)cout<<v[i].first<<" "<<v[i].second<<endl;
#define all(x) x.begin(),x.end()
#define srt(x) sort(all(x))
#define cl(a,b) ceil(a/(double)b)
#define fors(n) for(ll i=0;i<n;i++)
long long binaryExponentiation(long long base, long long exponent) {
    long long result = 1;

    while (exponent > 0) {
        if (exponent % 2 == 1) {
            result *= base;  // If exponent is odd, multiply the result by the base
        }

        base *= base;  // Square the base
        exponent /= 2;  // Divide the exponent by 2
    }

    return result;
}
bool checkprime(ll n) {
    if (n <= 1) return false;
    if (n <= 3) return true;
    if (n % 2 == 0 || n % 3 == 0) return false;
    for (ll i = 5; i * i <= n; i += 6) {
        if (n % i == 0 || n % (i + 2) == 0) return false;
    }
    return true;
}

vi getFactorization(ll n) {
  
    vi factors;
    for (ll i = 2; i * i <= n; ++i) {
        if (n % i == 0) {
            factors.push_back(i);
            if (i != n / i) {
                factors.push_back(n / i);
            }
        }
    }
       return factors;
}
bool check_if_no_is_in_2_ki_power_any_x(ll n){
  if(!(n&(n-1)))return false;
  return true;
}
vector<ll>findpro(ll n){
 
  vector<ll>result;
  ll d=2;
  while(d*d<=n||n!=1){
    if(n%d==0){
      result.push_back(d);
      n=n/d;
    }else{
      while(n%d!=0)d++;
    }
  }
  return result;
}
ll gcd(ll a,ll b) {
    while (b != 0) {
        ll temp = b;
        b = a % b;
        a = temp;
    }
    return a;
}

class compare{
public:
  bool operator()(ll&a,ll&b){
    return a<b;
  }
};
class Node{
public:
  int val;
  char letter;
  Node*left;
  Node*right;
  Node(int val,char letter){
    this->letter=letter;
    this->val=val;
    left=NULL;
    right=NULL;
  }
};
ll bnsearch(ll low,ll high,vi &v,ll sum){
  if(sum>v[high])return high;
  while(low<high){
    ll plus=(low+high)/2;
    if(v[plus]>=sum)high=plus-1;
    else low=plus+1;
  }
  if(v[low]>=sum)return -1;
  else return low;
}

int main(){
  #ifdef FELIX
  auto _clock_start = chrono::high_resolution_clock::now();
  #endif
  ios::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
  #ifndef ONLINE_JUDGE
    freopen("input.in", "r", stdin);
    freopen("output.out", "w", stdout);
    freopen("error.out", "w", stderr);
  #endif

  ll t;
  cin>>t;
  while(t--){

    ll n;
    cin>>n;
    vector<pair<ll,ll>>v1;
    vector<pair<ll,ll>>v2;
    vector<ll>row1(n,0);
    vector<ll>row2(n,0);
    ip(row1,n);
    ip(row2,n);
    ll top=0;
    ll down=0;
    for(ll i=0;i<n;i++){
      if(row1[i]>=row2[i]){v1.push_back({row1[i],row2[i]});top+=row1[i];}
      else {v2.push_back({row1[i],row2[i]});down+=row2[i];}
    }
    ll ans=INT_MIN;
    for(ll i=0;i<v1.size();i++){
      ans=max(ans,top+v1[i].second+down);
    }
    for(ll i=0;i<v2.size();i++){
      ans=max(ans,top+down+v2[i].first);
    }
    cout<<ans<<endl;
  }
  return 0;
}