/** @xigua */
#include <stdio.h>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <cstring>
#include <queue>
#include <set>
#include <string>
#include <map>
#include <climits>
#define PI acos(-1)
using namespace std;
typedef long long ll;
typedef double db;
const int maxn = 1e4 + 5;
const ll mod = 1ll<<32;
const int INF = 1e8 + 5;
const ll inf = 1e15 + 5;
const db eps = 1e-6;
int mapp[105][105];
struct pos {ll x, y;
};ll get(ll x1, ll x2, ll y1, ll y2) {ll x = x2 - x1 + 1, y = y2 - y1 + 1;return x * (x + 1) / 2 * y * (y + 1) / 2;
}ll gao(int val, int n, int m) {ll dp[105][105] = {0};ll ans = 0;for (int i = 1; i <= n; i++) {ll sum = 0, a[105], b[105], cnt = 0;for (int j = 1; j <= m; j++) {if (mapp[i][j] == val)dp[i][j] = 0;else dp[i][j] = dp[i-1][j] + 1;int tmp = 1;while (cnt && a[cnt] > dp[i][j]) {sum -= a[cnt] * b[cnt];tmp += b[cnt]; // a维护高度，b维护宽度cnt--;}cnt++;a[cnt] = dp[i][j];b[cnt] = tmp;sum += a[cnt] * b[cnt];ans += sum;}}return ans;
}void solve() {ll n, m;cin >> n >> m;vector<pos> g[maxn];for (int i = 1; i <= n; i++) {for (int j = 1; j <= m; j++) {scanf("%d", mapp[i] + j);g[mapp[i][j]].push_back((pos){i, j});}}ll tot = 0, all = n * (n + 1) / 2 * m * (m + 1) / 2;    //所有矩阵的总数for (int i = 0; i < n * m; i++) {if (g[i].size() <= 13) {for (int st = 1; st < (1<<g[i].size()); st++) {ll xl = n + 1, xr = 0, yl = m + 1, yr = 0;int num = 0;for (int j = 0; j < g[i].size(); j++) {if ((1<<j) & st) {pos tmp = g[i][j]; num++;xl = min(xl, tmp.x); xr = max(xr, tmp.x);yl = min(yl, tmp.y); yr = max(yr, tmp.y);}}//容斥if (num & 1) tot += (ll) xl * yl * (n - xr + 1) * (m - yr + 1);else tot -= (ll) xl * yl * (n - xr + 1) * (m - yr + 1);}}else {tot += all - gao(i, n, m);}}printf("%.9f\n", (db)tot / (db)(all));
}int main() {int t = 1, cas = 1;//freopen("in.txt", "r", stdin);// freopen("out.txt", "w", stdout);scanf("%d", &t);while(t--) {// printf("Case %d: ", cas++);solve();}return 0;
}