#include <cmath>
#include <cstdio>
#include <iostream>using namespace std;#define eps 1e-8
#define maxn 205int ai[maxn][maxn],bi[maxn][maxn],ma,mi,pre[maxn],s,t,h,tail,cnt;
int n,head[maxn],E[maxn*maxn],V[maxn*maxn],F[maxn*maxn],que[maxn<<8];double W[maxn*maxn],suma,sumb,dis[maxn];bool if_[maxn];inline void in(int &now_)
{register int now=0;register char Cget=getchar();while(Cget>'9'||Cget<'0') Cget=getchar();while(Cget>='0'&&Cget<='9'){now=now*10+Cget-'0';Cget=getchar();}now_=now;
}inline bool spfa()
{for(int i=s;i<=t;i++) dis[i]=-1e6,pre[i]=-1,if_[i]=false;h=maxn<<4,tail=h+1,que[h]=s,dis[s]=0,if_[s]=true;while(h<tail){register int now=que[h++];if_[now]=false;for(register int i=head[now];i;i=E[i]){if(dis[V[i]]<dis[now]+W[i]&&F[i]>0){pre[V[i]]=i;dis[V[i]]=dis[now]+W[i];if(!if_[V[i]]){if_[V[i]]=true;if(dis[V[i]]>dis[que[h]]) que[--h]=V[i];else que[tail++]=V[i];}}}}return dis[t]!=-1e6;
}int main()
{freopen("ball.in","r",stdin);freopen("ball.out","w",stdout);in(n);t=n<<1|1;for(register int i=1;i<=n;i++){ma=0;for(register int j=1;j<=n;j++) in(ai[i][j]),ma=max(ma,ai[i][j]);suma+=ma;}for(register int i=1;i<=n;i++){mi=0x7fffffff;for(register int j=1;j<=n;j++) in(bi[i][j]),mi=min(mi,bi[i][j]);sumb+=mi;}double l=0,r=suma/sumb,mid,ans;while(r-l>eps){mid=(l+r)/2.0,cnt=1;for(register int i=s;i<=t;i++) head[i]=0;for(register int i=1;i<=n;i++){E[++cnt]=head[s],V[cnt]=i,F[cnt]=1,W[cnt]=0,head[s]=cnt;E[++cnt]=head[i],V[cnt]=s,F[cnt]=0,W[cnt]=0,head[i]=cnt;E[++cnt]=head[t],V[cnt]=i+n,F[cnt]=0,W[cnt]=0,head[t]=cnt;E[++cnt]=head[i+n],V[cnt]=t,F[cnt]=1,W[cnt]=0,head[i+n]=cnt;for(register int j=1;j<=n;j++){register int o=j+n;register double pos=(double)ai[i][j]-mid*bi[i][j];E[++cnt]=head[i],V[cnt]=o,F[cnt]=1,W[cnt]=pos,head[i]=cnt;E[++cnt]=head[o],V[cnt]=i,F[cnt]=0,W[cnt]=-pos,head[o]=cnt;}}double sum=0;while(spfa()){sum+=dis[t];register int now=t;while(pre[now]!=-1) F[pre[now]]--,F[pre[now]^1]++,now=V[pre[now]^1];}if(sum>0) ans=mid,l=mid+eps;else r=mid-eps;}printf("%.6lf",ans);fclose(stdin),fclose(stdout);return 0;
}