#include <bits/stdc++.h>

using i64 = long long;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int n, k;
    std::cin >> n >> k;

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

    std::vector<double> sum(n + 1, 0);
    for (int i = 0; i < n; ++i) {
        sum[i + 1] = sum[i] + a[i];
    }

    std::vector<std::vector<double>> dp(n + 1, std::vector<double>(k + 1, -1e9));
    dp[0][0] = 1e9;

    for (int j = 1; j <= k; ++j) {
        for (int i = j; i <= n; ++i) {
            for (int p = j - 1; p < i; ++p) {
                double avg = 1.0 * (sum[i] - sum[p]) / (i - p);
                dp[i][j] = std::max(dp[i][j], std::min(dp[p][j - 1], avg));
            }
        }
    }

    std::cout << std::fixed << std::setprecision(9) << dp[n][k];
    return 0;
}