#include<bits/stdc++.h>

using namespace std;

const int N=;

struct edge{int u,v,w,nxt;double c;}e[N*N*];

queue<int>q;

int n,S,T,ecnt,hd[N],vis[N],pre[N];

double a[N][N],b[N][N],d[N];

void adde(int x,int y,int z,double c)

{

    e[++ecnt]=(edge){x,y,z,hd[x],c},hd[x]=ecnt;

    e[++ecnt]=(edge){y,x,,hd[y],-c},hd[y]=ecnt;

}

bool spfa()

{

    for(int i=S;i<=T;i++)d[i]=-1e18,pre[i]=;

    d[S]=,q.push(S);

    while(!q.empty())

    {

        int u=q.front();q.pop();

        vis[u]=;

        for(int i=hd[u];i;i=e[i].nxt)

        if(e[i].w&&d[u]+e[i].c>d[e[i].v])

        {

            pre[e[i].v]=i,d[e[i].v]=d[u]+e[i].c;

            if(!vis[e[i].v])q.push(e[i].v),vis[e[i].v]=;

        }

    }

    return d[T]>-1e18;

}

bool check()

{

    double ret=;

    while(spfa())

    {

        int mn=1e9+;

        for(int i=pre[T];i;i=pre[e[i^].v])mn=min(mn,e[i].w);

        for(int i=pre[T];i;i=pre[e[i^].v])e[i].w-=mn,e[i^].w+=mn;

        ret+=mn*d[T];

    }

    return ret>;

}

int main()

{

    scanf("%d",&n),T=*n+;

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

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

    double l=,r=,mid;

    while(r-l>1e-)

    {

        mid=(l+r)/;

        ecnt=;

        memset(hd,,sizeof hd);

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

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

        adde(i,j+n,,a[i][j]-mid*b[i][j]);

        for(int i=;i<=n;i++)adde(S,i,,),adde(i+n,T,,);

        if(check())l=mid;else r=mid;

    }

    printf("%.6lf",l);

}