#pragma comment(linker, "/STACK:1024000000,1024000000")

#include <cstdio>

#include <string>

#include <cstdlib>

#include <cmath>

#include <iostream>

#include <cstring>

#include <set>

#include <queue>

#include <algorithm>

#include <vector>

#include <map>

#include <cctype>

#include <cmath>

#include <stack>

#include <sstream>

#include <list>

#include <assert.h>

#include <bitset>

#define debug() puts("++++");

#define gcd(a, b) __gcd(a, b)

#define lson l,m,rt<<1

#define rson m+1,r,rt<<1|1

#define fi first

#define se second

#define pb push_back

#define sqr(x) ((x)*(x))

#define ms(a,b) memset(a, b, sizeof a)

#define sz size()

#define pu push_up

#define pd push_down

#define cl clear()

//#define all 1,n,1

#define FOR(i,x,n)  for(int i = (x); i < (n); ++i)

#define freopenr freopen("in.txt", "r", stdin)

#define freopenw freopen("out.txt", "w", stdout)

using namespace std;

typedef long long LL;

typedef unsigned long long ULL;

typedef pair<int, int> P;

const int INF = 0x3f3f3f3f;

const double inf = 1e20;

const double PI = acos(-1.0);

const double eps = 1e-8;

const int maxn = 50 * 50 + 100 + 10;

const int maxm = 1e5 + 10;

const int mod = 50007;

const int dr[] = {-1, 0, 1, 0};

const int dc[] = {0, -1, 0, 1};

const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};

int n, m;

const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

inline bool is_in(int r, int c) {

  return r >= 0 && r < n && c >= 0 && c < m;

}

struct Edge{

  int from, to, cap, flow, cost;

};

struct MinCostMaxFlow{

  int n, m, s, t;

  vector<Edge> edges;

  vector<int> G[maxn];

  bool inq[maxn];

  int d[maxn];

  int p[maxn];

  int a[maxn];

  void init(int n){

    this-> n = n;

    for(int i = 0; i < n; ++i)  G[i].cl;

    edges.cl;

  }

  void addEdge(int from, int to, int cap, int cost){

    edges.pb((Edge){from, to, cap, 0, cost});

    edges.pb((Edge){to, from, 0, 0, -cost});

    m = edges.sz;

    G[from].pb(m - 2);

    G[to].pb(m - 1);

  }

  bool bellman(int &flow, int &cost){

    ms(d, INF);  ms(inq, 0);

    inq[s] = 1;  d[s] = 0;  a[s] = INF;  p[s] = 0;

    queue<int> q;

    q.push(s);

    while(!q.empty()){

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

      inq[u] = 0;

      for(int i = 0; i < G[u].sz; ++i){

        Edge &e = edges[G[u][i]];

        if(e.cap > e.flow && d[e.to] > d[u] + e.cost){

          d[e.to] = d[u] + e.cost;

          p[e.to] = G[u][i];

          a[e.to] = min(a[u], e.cap - e.flow);

          if(!inq[e.to]){ q.push(e.to);  inq[e.to] = 1; }

        }

      }

    }

    if(d[t] == INF)  return false;

    cost += a[t] * d[t];

    flow += a[t];

    int u = t;

    while(u != s){

      edges[p[u]].flow += a[t];

      edges[p[u]^1].flow -= a[t];

      u = edges[p[u]].from;

    }

    return true;

  }

  int mincostmaxflow(int s, int t){

    this->s = s;  this->t = t;

    int flow = 0, cost = 0;

    while(bellman(flow, cost));

    return cost;

  }

};

MinCostMaxFlow mcmf;

int a[55][55];

int main(){

  int T;  cin >> T;

  while(T--){

    scanf("%d %d", &n, &m);

    int s = 0, t = n * m + n + 2;

    mcmf.init(t + 10);

    for(int i = 1; i <= n; ++i)

      for(int j = 1; j <= m; ++j)

        scanf("%d", a[i] + j);

    for(int i = 1; i <= n; ++i){

      mcmf.addEdge(s, i, 1, 0);

      for(int j = 1; j <= m; ++j)

        for(int k = 1; k <= n; ++k){

          mcmf.addEdge(i, j * n + k, 1, k * a[i][j]);

          if(i == 1)  mcmf.addEdge(j * n + k, t, 1, 0);

        }

    }

    printf("%f\n", mcmf.mincostmaxflow(s, t) * 1. / n);

  }

  return 0;

}