// luogu-judger-enable-o2
#pragma GCC optimize(3)
#include<bits/stdc++.h>
#define inf 1e5
#define eps 1e-6
#define mid (l+r)/2
using namespace std;

queue<int> Q;
struct node{
	int x,y,c,next;
	double d;
}a[30010];
int n,len=0,st,ed;
int last[210],last2[210];
double b1[110][110],b2[110][110],h[210];

void ins(int x,int y,int c,double d)
{
    a[++len].y=y;a[len].c=c;a[len].d=d;
	a[len].next=last[x];last[x]=len;
    a[++len].y=x;a[len].c=0;a[len].d=-d;
	a[len].next=last[y];last[y]=len;
}

bool bfs()
{
    for(int i=st;i<=ed;i++) a[i].x=-1,h[i]=inf;
    h[st]=0.0;
	Q.push(st);
    while(!Q.empty())
    {
        int x=Q.front();Q.pop();
        for(int i=last[x];i;i=a[i].next)
        {
        	int y=a[i].y;
        	if(a[i].c && h[y]>h[x]+a[i].d)
            {
            	h[y]=h[x]+a[i].d;
				a[y].x=x;last2[y]=i;
				Q.push(y);
            }
        }
    }
    if(a[ed].x!=-1) return true;
    return false;
}

double dfs()
{
    double ans=0;
    while(bfs())
    {
        int tot=inf;
        for(int i=ed;i!=st;i=a[i].x) tot=min(tot,a[last2[i]].c);
        ans+=tot*h[ed];
        for(int i=ed;i!=st;i=a[i].x) a[last2[i]].c-=tot,a[last2[i]^1].c+=tot;
    }
    return ans;
}

bool check(double x)
{
    memset(last,0,sizeof(last));
    len=1;
    for(int i=1;i<=n;i++) ins(st,i,1,0);
    for(int i=1;i<=n;i++) ins(i+n,ed,1,0);
    for(int i=1;i<=n;i++)
        for(int j=1;j<=n;j++) ins(i,j+n,1,x*b2[i][j]-b1[i][j]);
    if(dfs()<0) return true;
    return false;
}

int main()
{
    scanf("%d",&n);st=0;ed=2*n+1;
    for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++) scanf("%lf",&b1[i][j]);
    for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++) scanf("%lf",&b2[i][j]);
    double l=0.0,r=10000000.0;
    while(l<=r)
    {
        if(check(mid)) l=mid+eps;
        else r=mid-eps;
    }
    printf("%.6lf",mid);
    return 0;
}