Midstream.

#include<bits/stdc++.h>

#define int long long int
#define rep(a,b,c) for(int a=b;a<c;a++)
#define repm(a,b,c) for(int a=(b-1);a>=c;a--)
#define pb push_back
#define str string
#define sf(a) scanfs("%d",&a)
#define pb push_back
#define mp make_pair
#define Fi first
#define Se second
#define ALL(v) (v).begin(), (v).end()

using namespace std;

const int INF = 1e18 + 9;
const int Mod = 1e9 + 7;
inline int replac(str s){double ans=0;rep(i,0,s.length()){ans+=(s[i]-'0')*pow(10,s.length()-i-1);}return (int)ans;}
inline string numstr(int m){str s="";while(m>0){char c;int a=m/10;if(a>0)a=m%(a*10);else a=m;c=(char)('0'+a);s+=c;m/=10;}str st="";for(int i=s.size()-1;i>=0;i--){st+=s[i];}return st;}
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef vector<pii> vii;
vi a,b;
vector<double> f;
signed main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n,m;
    double d;
    while(1){
    cin >> d;
    if(d==0)break;
    a.clear();b.clear();f.clear();
    cin >> n >> m;
    double sa=0;
    double x;
    a.pb(0);
    rep(i,0,n-1){
        cin >> x;
        a.pb(x);
        f.pb((sa+x)/2);
        //cout << (sa+x)/2 << "sa" << endl;
        sa=x;
    }
    f.pb((x+d)/2);
    //cout <<(x+d)/2 << "sa" << endl;
    rep(i,0,m){
        int x;
        cin >> x;
        b.pb(x);
    }
    sort(ALL(a));
    sort(ALL(b));
    //for(double v:f){
      //  cout << v << "v" << endl ;
    //}
    int ans=0,cou=0;
    bool ok=false;
    rep(i,0,m){
        //if(f[cou]<b[i]){
        if(f[0]>b[i]){
            ans+=b[i];
        }else if(f[n-1]<=b[i]){
            ans+=(d-b[i]);
        }else {
            rep(j,cou,n){
                if(f[j]>=b[i]){
                    //cout << cou << " cou " << j << endl;
                    cou=j;
                    ans+=abs(a[cou]-b[i]);
                    break;
                }
            }
        }
        //cout << ans << " " << cou << endl;
    }
    cout << ans << endl;
    }
    return 0;
}