#include <bits/stdc++.h>
#define st first
#define nd second
using lint = long long;
constexpr int mod = 998244353;
constexpr int inf = 0x3f3f3f3f;
constexpr lint linf = 0x3f3f3f3f3f3f3f3f;
using namespace std;

int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    int n, k;
    cin>>n>>k;
    vector<int>a(n);
    for(int i=0;i<n;i++) cin>>a[i];
    double lo = 0, hi = 1000;
    for(int z=0;z<40;z++){
        double mid = (lo + hi) / 2;
        vector<double>b(n);
        for(int i=0;i<n;i++) b[i] = a[i] - mid;
        vector<double>dp(1);
        dp[0] = 0;
        double pref = 0;
        for(int i=0;i<n;i++){
            pref += b[i];
            if(pref < 0) continue;
            int it = int(lower_bound(dp.begin(), dp.end(), pref) - dp.begin());
            if(it == dp.size()) dp.push_back(pref);
            else dp[it+1] = min(dp[it+1], pref);
        }
        if(dp.size() > k) lo = mid;
        else hi = mid;
    }
    cout<<fixed<<setprecision(6);
    cout<<lo<<"\n";
    return 0;
}