#include<cstdlib>
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<queue>
#include<set>
#include<cstring>
#include<map>
using namespace std;
const int MAXN = (int) 105;
const int INF = (int) 0x3f3f3f3f;
typedef long long LL;

int dist;
int M,N;
int S[MAXN];
int D[MAXN];
LL ans;
LL out_time[MAXN];
map<LL,set<int> > mp;
struct permutation{
    int a[10];
}per;
int percnt;
vector<permutation> P;

bool is_judge(){
    mp.clear();
    for(int i=2;i<=N;i++)if(out_time[i]<=out_time[i-1]) return false;
//    for(int i=1;i<=n;i++) printf("%lld ",out_time[i]);
//    printf("\n");
    for(int i=1;i<N;i++){
        for(int j=i+1;j<=N;j++){
            if(S[i]<=S[j]) continue;
            if((out_time[j]-out_time[i])/(S[i]-S[j])>=dist) continue;
            if((out_time[j]-out_time[i])%(S[i]-S[j])!=0) return false;
            int tmpD=(out_time[j]-out_time[i])/(S[i]-S[j]);
            int ok=0;
            for(int k=1;k<=M;k++){
                if(D[k]==tmpD) ok=1;
            }
//            printf("ok = %d! , tmpD = %-12d , i = %d , j = %d\n",ok,tmpD,i,j);
            if(!ok) return false;
            if(mp.count(tmpD)){
                if(mp[tmpD].count(i)) return false;
                if(mp[tmpD].count(j)) return false;
            }
            mp[tmpD].insert(i);
            mp[tmpD].insert(j);
        }
    }
    return true;
}

void update(){
    for(int i=N;i>=1;i--) out_time[i]-=out_time[1];
//    for(int i=1;i<N;i++)if(out_time[i]>=out_time[i+1]) return;
//    for(int i=1;i<=N;i++) printf("%lld ",out_time[i]);
//    printf("\n");
    if(!is_judge()) return;
    LL tmpans=0;
    for(int i=1;i<=N;i++){
        LL tmp=out_time[i]+(LL)dist*S[i];
        tmpans=max(tmpans,tmp);
    }
//    if(tmpans==6577480535){
//        for(int i=1;i<=N;i++) printf("%lld ",out_time[i]);
//        printf("\n");
//        if(is_judge()) printf("true!\n");
//        else printf("false!\n");
//        exit(0xff);
//    }
//    for(int i=1;i<=n;i++) printf("%lld ",out_time[i]);
//    printf(" : tmpans = %lld\n",tmpans);
    ans=min(ans,tmpans);
}

int mark[MAXN];
void DFS1(int cur){
    if(cur>N){
        per.a[0]=1;
        P.push_back(per);
        return;
    }
    for(int i=1;i<=N;i++)if(!mark[i]){
        per.a[++percnt]=i;
        mark[i]=1;
        DFS1(cur+1);
        percnt--;
        mark[i]=0;
    }
}

void DFS2(int curid,const permutation& now){
    if(curid>N){
        update();
        return;
    }
    int cur=now.a[curid];
    if(curid==1){
        out_time[cur]=0;
        DFS2(curid+1,now);
        return;
    }

    for(int t=1;t<curid;t++){
        int pre=now.a[t];
        if(cur<pre){
            out_time[cur]=out_time[pre]-1;
            DFS2(curid+1,now);
            for(int i=1;i<=M;i++){
                LL dt=D[i];
                out_time[cur]=out_time[pre]-dt*(S[cur]-S[pre]);
    //            printf("%d-%d : %lld->%lld\n",pre,cur,out_time[pre],out_time[cur]);
                DFS2(curid+1,now);
            }
        }
        if(cur>pre){
            out_time[cur]=out_time[pre]+1;
            DFS2(curid+1,now);
            for(int i=1;i<=M;i++){
                LL dt=D[i];
                out_time[cur]=out_time[pre]+dt*(S[pre]-S[cur]);
    //            printf("%d-%d : %lld->%lld\n",pre,cur,out_time[pre],out_time[cur]);
                DFS2(curid+1,now);
            }
        }
    }
}

void solve(){
    for(int perid=0;perid<P.size();perid++){
        DFS2(1,P[perid]);
    }
}

void work(){
    scanf("%d%d",&dist,&N);
    for(int i=1;i<=N;i++) scanf("%d",&S[i]);
    scanf("%d",&M);
    for(int i=1;i<=M;i++) scanf("%d",&D[i]);
    D[++M]=dist;
    ans=(LL)INF*INF;
    DFS1(1);
//    printf("Pcnt = %d\n",P.size());
//    for(int i=0;i<P.size();i++){
//        for(int k=1;k<=N;k++) printf("%d ",P[i].a[k]);
//        printf("\n");
//    }
    solve();
    printf("%lld\n",ans);
}

int main(){
#ifdef NNever
//freopen("data.in","r",stdin);
///freopen("out.txt","w",stdout);
#endif // NNever
    work();
    return 0;
}

/*
input
60516263
5
45
16
94
71
91
4
20586550
54017689
36941264
49153094

output
6577480535
*/



Measured memory_bytes: 3320