#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<deque>
#include<vector>
#include<string>
#include<math.h>
using namespace std;

#define INF 1000000000
#define lint long long
#define pb push_back
#define mp make_pair
#define MOD 1000000007

lint a[1005][2006];
long double d[1005][2005];
long double p[1005][2005];
int main()
{
    int tc;
    scanf("%d",&tc);
    while(tc--)
    {
        int n,i,j;
        scanf("%d",&n);
        for(i=1;i<=n;++i)
        {
            for(j=1;j<=2*i;++j)
            {
                scanf("%lld",&a[i][j]);
            }
        }
        for(i=1;i<=n+1;++i)
        {
            for(j=1;j<=i;++j)
            {
                d[i][j]=0;
                p[i][j]=0;
            }
        }
        d[1][1]=0;
        p[1][1]=1;
        for(i=1;i<=n;++i)
        {
            for(j=1;j<=i;++j)
            {
                //cout<<i<<" x "<<j<<endl;
                //cout<<d[i][j]<<" "<<p[i][j]<<endl;

                int len1, len2;
                len1=a[i][2*j-1];
                len2=a[i][2*j];
                double p1;
                double p2;

                if(len1==len2)
                {
                    p1=0.5;
                    p2=0.5;
                }
                else if(len1<len2)
                {
                    p1=1;
                    p2=0;
                }
                else
                {
                    p1=0;
                    p2=1;
                }
                //cout <<p1<<" "<<p2<<endl;
                //cout<<len1<<" "<<len2<<endl;

                d[i+1][j]+=p1*(p[i][j]*len1+d[i][j]);
                d[i+1][j+1]+=p2*(p[i][j]*len2+d[i][j]);
                p[i+1][j]+=p1*p[i][j];
                p[i+1][j+1]+=p2*p[i][j];
                //cout<<i+1<<" "<<j<<" "<<d[i+1][j]<<"   ";
                //cout<<i+1<<" "<<j+1<<" "<<d[i+1][j+1]<<endl;
            }
        }
        double ans=0;
        for(i=1;i<=n+1;++i)
        {
            ans+=d[n+1][i];
            //cout << d[n+1][i]<<" ";
        }
        printf("%.9lf\n",ans);
    }
    return 0;
}