#include <bits/stdc++.h>
using namespace std;
const int maxn = 100 + 10;
double dp[2][maxn][maxn];
double s[maxn][maxn], s2[maxn][maxn];
inline double S(int x1, int y1, int x2, int y2) {
  return s[x2][y2] - s[x2][y1 - 1] - s[x1 - 1][y2] + s[x1 - 1][y1 - 1];
}
inline double S2(int x1, int y1, int x2, int y2) {
  return s2[x2][y2] - s2[x1 - 1][y1 - 1];
}
int a[maxn];
int main() {
  int n, k;
  scanf("%d%d", &n, &k);
  k = min(k, 1000);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  for (int m = 1; m <= k; m++) {
    for (int i = 1; i <= n + 1; i++)
      for (int j = 1; j <= n + 1; j++)
        s[i][j] =
            s[i - 1][j] + s[i][j - 1] - s[i - 1][j - 1] + dp[(m + 1) % 2][i][j],
        s2[i][j] = s2[i - 1][j - 1] + dp[(m + 1) % 2][i][j];
    for (int i = 1; i <= n; i++)
      for (int j = i + 1; j <= n; j++) {
        double &d = dp[m % 2][i][j];
        d = 0;
        for (int x = 1; x <= i; x++)
          d += S(x, j, x + j - i - 1, j) +
               (n - j + 1 - S2(x, x + j - i, x + n - j, x + n - i));
        for (int x = i + 1; x <= j; x++) d += S(i, x, i, x + n - j);
        int mul = (n - j + 1) * (n - j) / 2 + i * (i - 1) / 2 +
                  (j - i) * (j - i - 1) / 2;
        d += mul * dp[(m + 1) % 2][i][j];
        d /= (n * (n + 1) / 2);
      }
  }
  double ans = 0;
  for (int i = 1; i <= n; i++)
    for (int j = i + 1; j <= n; j++)
      ans += (a[i] > a[j] ? (1 - dp[k % 2][i][j]) : dp[k % 2][i][j]);
  printf("%.10f\n", ans);
}
