#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n, k;
  cin >> n >> k;
  vector<int> a(n + 1);
  for (int i = 1; i <= n; ++i) {
    cin >> a[i];
  }
  int u = 0, v = 1;
  vector<vector<double>> d[2];
  d[u].assign(n + 1, vector<double>(n + 1));
  for (int i = 1; i <= n; ++i) {
    for (int j = i + 1; j <= n; ++j) {
      if (a[i] < a[j]) {
        d[u][i][j] = 1.0;
      } else {
        d[u][j][i] = 1.0;
      }
    }
  }
  double p = 2.0 / (n * (n + 1));
  for (; k--; swap(u, v)) {
    d[v].assign(n + 1, vector<double>(n + 1));
    for (int i = 1; i <= n; ++i) {
      for (int j = 1; j <= n; ++j) {
        if (i == j) {
          continue;
        }
        for (int x = 1; x <= n; ++x) {
          for (int y = x; y <= n; ++y) {
            int ni = i;
            if (x <= i && i <= y) {
              ni = x + y - i;
            }
            int nj = j;
            if (x <= j && j <= y) {
              nj = x + y - j;
            }
            d[v][ni][nj] += d[u][i][j] * p;
          }
        }
      }
    }
  }
  double ans = 0.0;
  for (int i = 1; i <= n; ++i) {
    for (int j = 1; j < i; ++j) {
      ans += d[u][i][j];
    }
  }
  cout << ans << endl;
}
void init() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.precision(10);
}
int main() {
  init();
  solve();
  return 0;
}
