n=int(input())
l=list(map(int,input().split()))
k=int(input())
l.sort()
import math
#二分探索
right=10**10+1
left=0
while right-left>0.0000000099:
    mid=(right+left)/2
    
    cnt=0
    for i in range(n):
        cnt+=math.floor(l[i]/mid)
    if cnt>=k:
        left=mid 
    else:
        right =mid
print(right)