#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <vector>
#include <queue>
#include <map>
#include <algorithm>
#include <set>
using namespace std;
#define MM(a) memset(a,0,sizeof(a))
typedef long long ll;
typedef unsigned long long ULL;
const int mod = 1000000007;
const double eps = 1e-10;
const int inf = 0x3f3f3f3f;
const int big=50000;
int max(int a,int b) {return a>b?a:b;};
int min(int a,int b) {return a<b?a:b;};
const int N = 500;
const int M=20000;
struct edge{
   int to,cap,cost,rev;
};
vector<edge> G[3000];
int w[55][3000],dist[3000],inq[3000],prel[3000],prev[3000];
int n,m,x,y,c;
void add_edge(int u,int v,int cap,int cost)
{
    G[u].push_back(edge{v,cap,cost,G[v].size()});
    G[v].push_back(edge{u,0,-cost,G[u].size()-1});
}
int mcost(int s,int t,int f)
{
    int mincost=0;
    while(f>0)
    {
      memset(dist,inf,sizeof(dist));
      memset(inq,0,sizeof(inq));
      dist[s]=0;
      queue<int> q;
      q.push(s);
      inq[s]=1;
      while(!q.empty())
      {
          int u=q.front();
          q.pop();
          inq[u]=0;
          //printf("///\n");
          //cout<<q.size()<<endl;
          for(int j=0;j<G[u].size();j++)
            {
                edge &e=G[u][j];
                if(e.cap>0&&dist[e.to]>dist[u]+e.cost)
                   {
                       dist[e.to]=dist[u]+e.cost;
                       prev[e.to]=u;
                       prel[e.to]=j;
                       if(!inq[e.to])
                       {
                           q.push(e.to);
                           inq[e.to]=1;
                       }
                   }
            }
       }
       int minn=inf;
       for(int i=t;i>s;)
       {
           int f=prev[i];
           int j=prel[i];
           minn=min(minn,G[f][j].cap);
           i=prev[i];
       }
       for(int i=t;i>s;)
       {
           int f=prev[i];
           int j=prel[i];
           G[f][j].cap-=minn;
           G[i][G[f][j].rev].cap+=minn;
           mincost+=G[f][j].cost;
           i=prev[i];
       }
       f-=minn;
    }
   // cout<<mincost<<"hhahhaha"<<endl;
    return mincost;
}
int main()
{
    int cas;
    cin>>cas;
    while(cas--)
    {
        scanf("%d %d",&n,&m);

        int s=0,t=n+n*m+1;
        memset(w,0,sizeof(w));

        for(int i=s;i<=t;i++)
            G[i].clear();

        for(int i=1;i<=n;i++)
          for(int j=1;j<=m;j++)
              scanf("%d",&w[i][j]);

        for(int i=1;i<=m;i++)
          for(int j=1;j<=n;j++)
            for(int k=1;k<=n;k++)
              add_edge(k,i*n+j,1,w[k][i]*j);

        for(int i=1;i<=n;i++)
              add_edge(s,i,1,0);

        for(int j=n+1;j<=n+n*m;j++)
              add_edge(j,t,1,0);

        printf("%.6f\n",((double)mcost(s,t,n))/n);
    }
    return 0;
}