#include <iostream>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <random>
#include <stdio.h>
#include <fstream>
#include <functional>
#include <cassert>
#include <unordered_map>
#include <bitset>
#include <chrono>
//#include <atcoder/all>


using namespace std;
//using namespace atcoder;






#define rep(i,n) for (int i=0;i<n;i+=1)
#define rrep(i,n) for (int i=n-1;i>-1;i--)
#define pb push_back
#define all(x) (x).begin(), (x).end()

#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << " )\n";

template<class T>
using vec = vector<T>;
template<class T>
using vvec = vec<vec<T>>;
template<class T>
using vvvec = vec<vvec<T>>;
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;


template<class T>
bool chmin(T &a, T b){
  if (a>b){
    a = b;
    return true;
  }
  return false;
}

template<class T>
bool chmax(T &a, T b){
  if (a<b){
    a = b;
    return true;
  }
  return false;
}

template<class T>
T sum(vec<T> x){
  T res=0;
  for (auto e:x){
    res += e;
  }
  return res;
}

template<class T>
void printv(vec<T> x){
  for (auto e:x){
    cout<<e<<" ";
  }
  cout<<endl;
}



template<class T,class U>
ostream& operator<<(ostream& os, const pair<T,U>& A){
  os << "(" << A.first <<", " << A.second << ")";
  return os;
}

template<class T>
ostream& operator<<(ostream& os, const set<T>& S){
  os << "set{";
  for (auto a:S){
    os << a;
    auto it = S.find(a);
    it++;
    if (it!=S.end()){
      os << ", ";
    }
  }
  os << "}";
  return os;
}

template<class T>
ostream& operator<<(ostream& os, const tuple<T,T,T>& a){
  auto [x,y,z] = a;
  os << "(" << x << ", " << y << ", " << z << ")";
  return os;
}

template<class T>
ostream& operator<<(ostream& os, const map<ll,T>& A){
  os << "map{";
  for (auto e:A){
    os << e.first;
    os << ":";
    os << e.second;
    os << ", ";
  }
  os << "}";
  return os;
}

template<class T>
ostream& operator<<(ostream& os, const vec<T>& A){
  os << "[";
  rep(i,A.size()){
    os << A[i];
    if (i!=A.size()-1){
      os << ", ";
    }
  }
  os << "]" ;
  return os;
}


template <class T> void mkuni(vector<T>& v) {
    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());
}

template <class T> int lwb(const vector<T>& v, const T& x) {
    return distance(v.begin(), lower_bound(v.begin(), v.end(), x));
}



void solve(){
    int N,K;
    cin>>N>>K;
    vec<int> A(N);
    rep(i,N) cin>>A[i];

    auto cond = [&](double x){
        vec<double> cum(N+1,0);
        rep(i,N){
            cum[i+1] = cum[i] + A[i] - x;
        }
        vec<double> dp = {0};
        for (int i=1;i<N;i++){
            if (dp.back() <= cum[i]){
                dp.push_back(cum[i]);
                continue;
            }
            int idx = lwb(dp,cum[i]);
            dp[idx] = cum[i];
        }
        if (dp.back() <= cum[N]){
            return int(dp.size());
        }
        else{
            return lwb(dp,cum[N]);
        }
    };

    double ok = 0,ng = 1001;

    rep(_,50){
        double mid = (ok+ng)/2;
        if (cond(mid) >= K){
            ok = mid;
        }
        else{
            ng = mid;
        }
    }

    cout << ok << "\n";
    

  

}


int main(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  cout << fixed << setprecision(15);

  int T = 1;
  while (T--){
    solve();
  }
    
}