#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;
typedef long long ll;
const int N=105;
const double eps=1e-9,INF=1e100;
inline int read(){
    char c=getchar();int x=0,f=1;
    while(c<'0'||c>'
 
9'){if(c=='-')f=-1;c=getchar();}
    while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}
    return x*f;
}
int n,c[N],sum,g[10][N];
double p[10][N];
double d[10],x;
void dp(){
    d[0]=0;
    for(int i=1;i<=7;i++){
        d[i]=INF;
        for(int j=1;j<=n;j++) if(p[i][j]){
            
 
double _=d[i-1]+c[j]-(1-p[i][j])*d[g[i][j]];
            d[i]=min(d[i],_/p[i][j]);
        }
    }
    printf("%.10lf",d[7]);
}
int main(){
//    freopen("in","r",stdin);
    n=read();
    for(int i=1;i<=n;i++) c[i]=read();
    for(int i=1;i<=7;i++){
        bool flag=0;
        for(int
 
 j=1;j<=n;j++) scanf("%lf",&p[i][j]),flag|=( abs(p[i][j])>eps );
        if(!flag) {puts("-1");return 0;}
    }
    for(int i=1;i<=7;i++) for(int j=1;j<=n;j++) g[i][j]=i-1-read();
    dp();
}