#include <fstream>
#include <queue>
#define DIM 100010
using namespace std;

ifstream fin ("fabrica.in");
ofstream fout ("fabrica.out");
priority_queue < pair<int,int>, vector <pair<int,int> >, greater <pair<int,int> > > H;
int n,nra,nrb,i,pas,maxi,val;
int v[DIM],w[DIM];
int main (){

    fin>>n>>nra>>nrb;
    for (i=1;i<=nra;i++){
        fin>>v[i];
        H.push(make_pair(v[i],i));
    }
    for (i=1;i<=nrb;i++)
        fin>>w[i];
    pas = 1;
    while (pas <= n){

        val = H.top().first;
        H.pop();
        maxi = max (maxi,val);
        H.push (make_pair(v[H.top().second]+val,H.top().second));

        pas++;
    }
    fout<<maxi;


    return 0;
}