#include <bits/stdc++.h>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n,k,tmp,r;
vector<int> a,b;
cin >> n;
for (int q1234 = 0; q1234 < n; q1234++){
cin >> k;
r = 0;
for (int i = 0;i < k;i++){
cin >> tmp;
a.push_back(tmp);
}
for (int i = 0;i < k;i++){
cin >> tmp;
b.push_back(tmp);
}
sort(a.begin(),a.end());
sort(b.begin(),b.end());
reverse(a.begin(),a.end());
for (int j =0;j<k;j++){
r+=max(a[j],b[j]);
}
cout << r << endl;
a.clear();
b.clear();
}
}