#include <bits/stdc++.h>
using namespace std;
template <class T>
inline bool RD(T &ret) {
  char c;
  int sgn;
  if (c = getchar(), c == EOF) return 0;
  while (c != '-' && (c < '0' || c > '9')) c = getchar();
  sgn = (c == '-') ? -1 : 1, ret = (c == '-') ? 0 : (c - '0');
  while (c = getchar(), c >= '0' && c <= '9') ret = ret * 10 + (c - '0');
  ret *= sgn;
  return 1;
}
template <class T>
inline void PT(T x) {
  if (x < 0) putchar('-'), x = -x;
  if (x > 9) PT(x / 10);
  putchar(x % 10 + '0');
}
const int N = 33;
const int K = 222;
double dp[K][N][N];
int a[N];
int main() {
  int n, m;
  cin >> n >> m;
  for (int i = 1; i <= int(n); i++) RD(a[i]);
  for (int i = 1; i <= int(n); i++)
    for (int j = 1; j <= int(i - 1); j++) dp[0][j][i] = 1.0;
  double P = 1.0 / (n * (n + 1) / 2.0);
  for (int c = 1; c <= int(m); c++)
    for (int r = 1; r <= int(n); r++)
      for (int l = 1; l <= int(r); l++)
        for (int i = 1; i <= n; i++)
          for (int j = i + 1; j <= n; j++) {
            int ii = i, jj = j;
            if (r >= ii && ii >= l) ii = r + l - ii;
            if (l <= jj && jj <= r) jj = r + l - jj;
            if (ii > jj) swap(ii, jj);
            if (l <= i && j <= r)
              dp[c][ii][jj] += (1 - dp[c - 1][i][j]) * P;
            else
              dp[c][ii][jj] += dp[c - 1][i][j] * P;
          }
  double ans = 0;
  for (int j = 1; j <= int(n); j++)
    for (int i = 1; i <= int(j - 1); i++)
      if (a[i] > a[j])
        ans += dp[m][i][j];
      else
        ans += 1 - dp[m][i][j];
  printf("%.10f\n", ans);
}
