#include <cstdio>

 #include <cstring>

 #include <algorithm>

 #include <queue>

 #include <cmath>

 #define maxn 10000

 using namespace std;

 const int inf=<<;

 int n,m,l,x,y;

 double c,f;

 double cap[][],flow[][];

 int p[];

 double a[];

 void EK(int s)

 {

    queue<int>q;

    memset(flow,,sizeof(flow));

    f=;

    for(; ;)

    {

        memset(a,,sizeof(a));

        memset(p,-,sizeof(p));

        a[s]=inf;

        q.push(s);

        while(!q.empty())

        {

            int u=q.front();

            q.pop();

            for(int v=; v<=m+n+; v++)

            {

                if(!a[v]&&cap[u][v]>flow[u][v])

                {

                    p[v]=u;

                    q.push(v);

                    a[v]=min(a[u],cap[u][v]-flow[u][v]);

                }

            }

        }

        if(a[m+n+]==) break;

        for(int u=m+n+; u!=; u=p[u])

        {

            flow[p[u]][u]+=a[m+n+];

            flow[u][p[u]]-=a[m+n+];

        }

        f+=a[m+n+];

    }

 }

 int main()

 {

     int T;

     scanf("%d",&T);

     while(T--)

     {

         memset(cap,,sizeof(cap));

         scanf("%d%d%d",&m,&n,&l);

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

         {

             scanf("%lf",&c);

             cap[][i]=log(c);

         }

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

         {

             scanf("%lf",&c);

             cap[i][m+n+]=log(c);

         }

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

         {

             scanf("%d%d",&x,&y);

             cap[x][m+y]=inf;

         }

         f=;

         EK();

         printf("%.4f\n",exp(f));

     }

     return ;

 }