#include<bits/stdc++.h>
#define MAXN 1007
using namespace std;
int n,m;
int station[MAXN];
long long speed[MAXN],start[MAXN];
vector< pair<long long,int> > st[MAXN];
long long arrive[MAXN][MAXN];
long long simulate(){
for(int i=1;i<=m;i++)st[i].clear();
for(int i=1;i<=n+1;i++){
arrive[1][i]=start[i];
st[1].push_back({start[i],i});
}
sort(st[1].begin(),st[1].end());
for(int i=2;i<=m;i++){
long long maxtim=0, pt=0;
long long dist=station[i]-station[i-1];
for(int f=0;f<n+1;f++){
int curr=st[i-1][f].second;
while(pt<n+1 and st[i-1][pt].first < arrive[i-1][curr]){
maxtim=max(maxtim,st[i-1][pt].first + dist*speed[st[i-1][pt].second]);
pt++;
}
arrive[i][curr]=max(maxtim , arrive[i-1][curr] + dist*speed[curr]);
st[i].push_back({arrive[i][curr],curr});
}
sort(st[i].begin(),st[i].end());
}
return arrive[m][n+1];
}
void init(int L, int N, vector<long long> T, vector<int> W, int X, int M, vector<int> S){
n=N; m=M;
speed[n+1]=X;
for(int i=1;i<=m;i++)station[i]=S[i-1];
for(int i=1;i<=n;i++)speed[i]=W[i-1];
for(int i=1;i<=n;i++)start[i]=T[i-1];
}
long long arrival_time(long long Y){
start[n+1]=Y;
return simulate();
}
/*int main(){
init(6, 4, {20, 10, 40, 0}, {5, 20, 20, 30}, 10, 4, {0, 1, 3, 6});
cout<<arrival_time(0)<<"\n";
cout<<arrival_time(50)<<"\n";
return 0;
}*/
