#include<bits/stdc++.h>
using namespace std;
using pii=pair<int,int>;
using ll=long long;
void solve() {
    int n,k; cin>>n>>k;
    vector<int> a(n),b(n);
    for(int i=0; i<n; i++) cin>>a[i];
    for(int i=0; i<n; i++) cin>>b[i];

    sort(a.begin(),a.end(),greater<int>());
    sort(b.begin(),b.end(),greater<int>());

    // for(auto i:a) cout<<i<<" ";
    // cout<<endl;
    // for(auto i:b) cout<<i<<" ";
    // cout<<endl;
    vector<int> va,vb;
    int cnt_a=0,cnt_b=0;
    // 9 7 6 4
    // 10 8 5 2
    for(int i=0; i<n; i++) {
        if(a[cnt_a]==b[cnt_b]) {
            va.push_back(a[cnt_a]);
            vb.push_back(b[cnt_b]);
            cnt_a++,cnt_b++;
            continue;
        }
        //A bp
        //ban

        if((cnt_b<b.size()&&a[cnt_a]<b[cnt_b])||cnt_a>=a.size()||va.size()>=k)
            cnt_b++;
        //pick
        else if((cnt_a<a.size()&&a[cnt_a]>b[cnt_b])||cnt_b>=b.size())
            va.push_back(a[cnt_a]),cnt_a++;

        //B bp
        //ban
        if((cnt_a<a.size()&&b[cnt_b]<a[cnt_a])||cnt_b>=b.size()||vb.size()>=k)
            cnt_a++;
        //pick
        else if((cnt_b<b.size()&&b[cnt_b]>a[cnt_a])||cnt_a>=a.size())
            vb.push_back(b[cnt_b]),cnt_b++;
    }

    // for(auto i:va) cout<<i<<" ";
    // cout<<endl;
    // for(auto i:vb) cout<<i<<" ";
    // cout<<endl;

    ll sum_a=0,sum_b=0;
    for(int i=0; i<va.size()&&i<k; i++)
        sum_a+=1ll*va[i];
    for(int i=0; i<vb.size()&&i<k; i++)
        sum_b+=1ll*vb[i];
    // cout<<sum_a<<" "<<sum_b<<endl;
    cout<<sum_a-sum_b;
}

int main(){
    ios::sync_with_stdio(false);cin.tie(nullptr);
    solve();
}