#include<cstdio>

 #include<cstring>

 #include<cstdlib>

 #include<cmath>

 #include<algorithm>

 #define eps 1e-7

 #define inf 999999999.0

 using namespace std;

 struct node

 {

     int x,y,next,other;

     double c;

 }a[];int len,last[];

 void ins(int x,int y,double c)

 {

     int k1,k2;

     k1=++len;

     a[len].x=x;a[len].y=y;a[len].c=c;

     a[len].next=last[x];last[x]=len;

     k2=++len;

     a[len].x=y;a[len].y=x;a[len].c=;

     a[len].next=last[y];last[y]=len;

     a[k1].other=k2;

     a[k2].other=k1;

 }

 int st,ed,n,m,head,tail;

 int list[],h[];

 bool bt_h()

 {

     memset(h,,sizeof(h));h[st]=;

     list[]=st;head=;tail=;

     while(head!=tail)

     {

         int x=list[head];

         for(int k=last[x];k;k=a[k].next)

         {

             int y=a[k].y;

             if(!h[y] && a[k].c>)

             {

                 h[y]=h[x]+;

                 list[tail++]=y;

             }

         }

         head++;

     }

     if(h[ed])return true;

     return false;

 }

 double find_flow(int x,double flow)

 {

     if(x==ed)return flow;

     double s=,t;

     for(int k=last[x];k;k=a[k].next)

     {

         int y=a[k].y;

         if(h[y]==h[x]+ && a[k].c> && s<flow)

         {

             s+=t=find_flow(y,min(a[k].c,flow-s));

             a[k].c-=t;a[a[k].other].c+=t;

         }

     }

     if(s==)h[x]=;

     return s;

 }

 double A[],B[];

 int map[][];

 bool check(double x)

 {

     double sum=0.0,ans=0.0;

     len=;memset(last,,sizeof(last));

     for(int i=;i<=m;i++)ins(st,i,x*B[i]);

     for(int i=;i<=m;i++)for(int j=;j<=n;j++)if(map[i][j]==)ins(i,j+m,inf);

     for(int i=;i<=n;i++)ins(i+m,ed,A[i]),sum+=A[i];

     while(bt_h())ans+=find_flow(st,inf);

     if(abs(ans-sum)<=eps)return true;

     return false;

 }

 int main()

 {

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

     st=n+m+,ed=st+;

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

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

             scanf("%d",&map[i][j]);

     double l=0.0,r=10000000.0,ans=0.0;

     while(l<=r)

     {

         double mid=(l+r)/;

         if(check(mid))ans=mid,r=mid-eps;

         else l=mid+eps;

     }

     printf("%.6lf\n",ans);

     return ;

 }