#include <map>
#include <set>
#include <array>
#include <cmath>
#include <deque>
#include <bitset>
#include <random>
#include <string>
#include <vector>
#include <cassert>
#include <complex>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <unordered_map>
#include <unordered_set>

using namespace std;

using ld = long double;

int get_seq(const vector<ld>& a) {
  vector<ld> val;
  for (ld x : a) {
    if (x < a[0] || x > a.back()) continue;
    int ind = upper_bound(val.begin(), val.end(), x) - val.begin();
    if (ind == val.size()) val.push_back(1e4);
    val[ind] = min(val[ind], x);
  }
  return val.size();
}


int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

  int n, k;
  cin >> n >> k;
  vector<int> a(n);
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
  }

  ld l = 0, r = 2e3;
  for (int _ = 0; _ < 60; ++_) {
    ld m = (l + r) / 2;
    vector<ld> pref = {0};
    for (int i = 0; i < n; ++i) {
      pref.push_back(pref[i] + a[i] - m);
    }
    if (get_seq(pref) >= k + 1) {
      l = m;
    } else {
      r = m;
    }
  }

  cout << fixed << setprecision(20);
  cout << (l + r) / 2 << "\n";

  
  return 0;
}