#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int Mod=998244353;
 
void solve() {
 
   int n,k;
   cin >> n >> k;
   vector<int> a(n),b(n),ans(n),ans2(n);
 
   for(int i=0;i<n;i++) cin >> a[i];
   for(int i=0;i<n;i++) cin >> b[i];
 
   for(int i=0;i<n;i++){
    ans[i]=max(a[i],b[i]);
    ans2[i]=min(a[i],b[i]);}
 
   sort(ans.rbegin(),ans.rend());
   sort(ans2.rbegin(),ans2.rend());
 
   ll out =0;
   for(int i=0;i<n;i++) out+=ans[i];
   for(int i=0;i<k-1;i++) out+=ans2[i];
 
   out+=1;
 
   cout << out << '\n';
 
}
 
int main(){ 
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
 
    int t;
    cin >> t;
    while (t--) solve();
 
 
    return 0;
}
 

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NQozIDMKMSAxIDEKMSAxIDEKMSAxCjEwMAoxCjMgMgoxMDAgMSAxCjIwMCAxIDEKNSAyCjk3IDU5IDUwIDg3IDM2Cjk1IDc3IDMzIDEzIDc0CjEwIDYKOTcgNTkgNTAgODcgMzYgOTUgNzcgMzMgMTMgNzQKOTEgMTQgODQgMzMgNTQgODkgNjggMzQgMTQgMTUK

5
3 3
1 1 1
1 1 1
1 1
100
1
3 2
100 1 1
200 1 1
5 2
97 59 50 87 36
95 77 33 13 74
10 6
97 59 50 87 36 95 77 33 13 74
91 14 84 33 54 89 68 34 14 15