1 #include<cstdio>
 2 #include<cstdlib>
 3 #include<cstring>
 4 #include<iostream>
 5 #include<algorithm>
 6 #include<cmath>
 7 using namespace std;
 8 #define Maxn 110
 9 const double eps=1e-10;
10 const double INF=1e12;
11
12 double a[Maxn][Maxn],b[Maxn][Maxn];
13
14 int visx[Maxn],visy[Maxn],match[Maxn];
15 double slack[Maxn],lx[Maxn],ly[Maxn];
16 int n;
17
18 bool ffind(double mid,int x,int nt)
19 {
20     visx[x]=nt;
21     for(int y=1;y<=n;y++) if(visy[y]!=nt)
22     {
23         if(fabs(lx[x]+ly[y]-(a[x][y]-mid*b[x][y]))<eps)
24         {
25             visy[y]=nt;
26             if(!match[y]||ffind(mid,match[y],nt))
27             {
28                 match[y]=x;
29                 return 1;
30             }
31         }
32         else slack[y]=min(slack[y],lx[x]+ly[y]-(a[x][y]-mid*b[x][y]));
33     }
34     return 0;
35 }
36
37 bool check(double mid)
38 {
39     for(int i=1;i<=n;i++) match[i]=0;
40     for(int i=1;i<=n;i++)
41     {
42         visx[i]=visy[i]=0;
43         lx[i]=-INF;ly[i]=0;
44         for(int j=1;j<=n;j++) lx[i]=max(lx[i],a[i][j]-mid*b[i][j]);
45     }int nt=0;
46     for(int i=1;i<=n;i++)
47     {
48         for(int j=1;j<=n;j++) slack[j]=INF;
49         while(1)
50         {
51             nt++;
52             if(ffind(mid,i,nt)) break;
53             double delta=INF;
54             for(int j=1;j<=n;j++) if(visy[j]!=nt) delta=min(delta,slack[j]);
55             for(int j=1;j<=n;j++)
56             {
57                 if(visx[j]==nt) lx[j]-=delta;
58                 if(visy[j]==nt) ly[j]+=delta;
59                 else if(fabs(INF-slack[j])<eps) slack[j]-=delta;
60             }
61         }
62     }
63     double ans=0;
64     for(int i=1;i<=n;i++) ans+=lx[i]+ly[i];
65     return ans>=0;
66 }
67
68 int main()
69 {
70     double l=0,r=0;
71     scanf("%d",&n);
72     for(int i=1;i<=n;i++) for(int j=1;j<=n;j++) scanf("%lf",&a[i][j]),r+=a[i][j];
73     for(int i=1;i<=n;i++) for(int j=1;j<=n;j++) scanf("%lf",&b[i][j]);
74     while(r-l>eps)
75     {
76         double mid=(l+r)/2;
77         if(check(mid)) l=mid;
78         else r=mid;
79     }
80     printf("%.6lf\n",l);
81     return 0;
82 }