# import pypyjit
# pypyjit.set_param('max_unroll_recursion=-1')
from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline


N = int(input())
L = list(map(int,input().split()))
K = int(input())

def is_ok(x):
    if x==0:
        return True
    tmp = 0
    for l in L:
        tmp += l//x
        
    return tmp>=K
    
x = 0
y = 10**9 + 1
INF = 10**9+100
for _ in range(100):
    mid = (y+x)/2
    if is_ok(mid):
        x = mid
    else:
        y = mid
print(x)