#include <bits/stdc++.h>
using namespace std;
#define debug(x) cerr << #x << " = " << (x) << endl;
#define Yes cout <<"Yes"<<"\n";
#define No cout <<"Impossible"<<"\n";
using ll = long long;
int main(){
int n,m,k; // 1 1 2
// 3 3 3
// 1 2 2
// 1 4 3
//hay varios disponibles
//cout<<"SAJHDJASHDK";
cin>>n>>m>>k;
vector<int> comida(n);
vector<int> chefs(m);
int sum=0;
int sumcomida =0;
if(k>m){
No
return 0;
} else{
for(int i =0;i<n;i++){
cin>>comida[i];
sumcomida+=comida[i];
if(comida[i]<k){
No
return 0;
}
}
for(int i =0;i<m;i++){
cin>>chefs[i];
sum+=chefs[i];
// 1 5 7 9 6 3
// 1 3 5 6 7 9
// 1 3 5 6
//C:\Users\User\Desktop\GitHub\ioi2025\ioiBOLTraining\week0
}
sort(chefs.begin(),chefs.end());
int rest=m-k;
int top = chefs.size()-1;
for(int i=0;i<rest;i++){
sum-=chefs[top-i];
}
int res = sum-sumcomida;
cout<<res;
}
return 0;
}
