#include<iostream>

 #include<cstring>

 #include<cstdio>

 #include<cmath>

 #include<algorithm>

 using namespace std;

 const int N=,M=;

 int c[M],d[M],dis[N][N],x,y,z,n,m,v,e;

 double f[M][M][],k[M];

 int main(){

     scanf("%d%d%d%d",&n,&m,&v,&e);

     for (int i=;i<=n;++i) scanf("%d",&c[i]);

     for (int i=;i<=n;++i) scanf("%d",&d[i]);

     for (int i=;i<=n;++i) scanf("%lf",&k[i]);

     for (int i=;i<=v;++i) for (int j=;j<=v;++j) dis[i][j]=1e9;

     for (int i=;i<=e;++i)

         scanf("%d%d%d",&x,&y,&z),dis[x][y]=dis[y][x]=min(dis[x][y],z);

     for (int i=;i<=v;++i) dis[i][i]=;

     for (int kkk=;kkk<=v;++kkk)

         for (int i=;i<=v;++i) if (i!=kkk)

             for (int j=;j<=v;++j)

                 if (i!=j&&j!=kkk) dis[i][j]=min(dis[i][kkk]+dis[kkk][j],dis[i][j]);

     for (int i=;i<=n;++i) for (int j=;j<=m;++j) f[i][j][]=f[i][j][]=1e9;

     f[][][]=f[][][]=0.00; f[][][]=0.00;

     for (int i=;i<=n;++i){

         int cc=dis[c[i-]][c[i]],cd=dis[c[i-]][d[i]],dc=dis[d[i-]][c[i]],dd=dis[d[i-]][d[i]];

         f[i][][]=f[i-][][]+cc;

         for (int j=;j<=min(i,m);++j){

             f[i][j][]=min(f[i-][j][]+cc,f[i-][j][]+cc*(-k[i-])+dc*k[i-]);

             f[i][j][]=min(f[i-][j-][]+cd*k[i]+cc*(-k[i]),

                            f[i-][j-][]+cc*(-k[i-])*(-k[i])+cd*(-k[i-])*k[i]+

                            dc*k[i-]*(-k[i])+dd*k[i-]*k[i]);

         }

     }

     double ans=1e9;

     for (int i=;i<=m;++i)

         ans=min(ans,min(f[n][i][],f[n][i][]));

     printf("%.2lf",ans);

 }