#include <bits/stdc++.h>

#define x first
#define y second
#define el '\n'
#define debug(x) cerr << #x << ": " << x << endl
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int N = 1e6 + 10, INF = 0x3f3f3f3f, mod = 998244353;

int lis(vector<double> &a) {
    int n = a.size(), len = 0;
    vector<double> f(n + 1);
    for (int i = 0; i < n; ++i) {
        int l = 0, r = len, mid;
        while (l < r) {
            mid = l + r + 1 >> 1;
            if (f[mid] < a[i]) l = mid;
            else r = mid - 1;
        }
        len = max(len, r + 1);
        f[r + 1] = a[i];
        if (i + 1 == n) return r;
    }
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int n, k; cin >> n >> k;
    vector<int> a(n);
    for (int i = 0; i < n; ++i) cin >> a[i];
    double l = 1, r = 1000, mid;
    for (int i = 0; i < 30; ++i) {
        mid = (l + r) / 2;
        vector<double> s(n + 1);
        for (int i = 1; i <= n; ++i) s[i] = s[i - 1] + a[i - 1] - mid;
        if (lis(s) >= k) l = mid;
        else r = mid;
    }
    cout << format("{:.8f}", l) << el;
}