#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:128000000")
using namespace std;
void solve();
void precalc();
clock_t start;
bool doing = true;
int main() {
  int t = 1;
  cout.sync_with_stdio(0);
  cin.tie(0);
  precalc();
  cout.precision(10);
  cout << fixed;
  start = clock();
  int testNum = 1;
  while (t--) {
    solve();
  }
  return 0;
}
void precalc() {}
int binpow(int q, int w, int mod) {
  if (!w) return 1;
  if (w & 1) return q * binpow(q, w - 1, mod) % mod;
  return binpow(q * q % mod, w / 2, mod);
}
int gcd(int q, int w) {
  while (w) {
    q %= w;
    swap(q, w);
  }
  return q;
}
int n, k;
long double dp[35][35][210];
int rev(int pos, int l, int r) {
  if (pos < l || pos > r) return pos;
  return l + r - pos;
}
void solve() {
  cin >> n >> k;
  vector<int> p(n);
  for (int i = 0; i < n; ++i) {
    cin >> p[i];
    --p[i];
  }
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < n; ++j) {
      if (i != j) {
        dp[i][j][0] = 1.0;
      }
    }
  }
  for (int step = 0; step < k; ++step) {
    for (int i = 0; i < n; ++i) {
      for (int j = 0; j < n; ++j) {
        if (i == j) continue;
        long double coef = 2.0 / n / (n + 1);
        for (int l = 0; l < n; ++l) {
          for (int r = l; r < n; ++r) {
            int x = rev(i, l, r), y = rev(j, l, r);
            if (x > y && i < j || x < y && i > j) {
              dp[i][j][step + 1] += (1 - dp[x][y][step]) * coef;
            } else {
              dp[i][j][step + 1] += dp[x][y][step] * coef;
            }
          }
        }
      }
    }
  }
  long double ans = 0;
  for (int i = 0; i < n; ++i) {
    for (int j = i + 1; j < n; ++j) {
      if (p[i] > p[j]) {
        ans += dp[i][j][k];
      } else {
        ans += 1.0 - dp[i][j][k];
      }
    }
  }
  cout << ans << "\n";
}
