from fractions import gcd
from datetime import date, timedelta
from heapq import*
import math
from collections import defaultdict, Counter
import sys
from bisect import *
sys.setrecursionlimit(10 ** 7)
MOD = 10 ** 9 + 7



def main():
    n = int(input())
    a = list(map(int, input().split()))
    k = int(input())

    def c(v):
        z = 0
        for i in range(n):
            z += a[i] // v
        return z 

    l, r = 0, 10 ** 12
    for i in range(200):
        m = (l + r) / 2
        if c(m) >= k:
            l = m
        else:
            r = m
    print(m)


if __name__ == '__main__':
    main()