#include <iostream>
#include <cmath>
using namespace std;

const int MAX_N = 200000;

int N, K;
long double L[MAX_N];

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> N;
    for(int x = 0; x < N; x++){
        cin >> L[x];
    }
    cin >> K;
    long double left = 0, right = 1000000000;
    for(int n = 0; n < 150; n++){
        double mid = (left + right)/2;
        int cnt = 0;
        for(int i = 0; i < N; i++){
            cnt += floor(L[i] / mid);
        }
        if(cnt >= K){
            left = mid;
        }else{
            right = mid;
        }
    }
    cout << left << endl;
    return 0;
}