N=int(raw_input())
L=map(int,raw_input().split())
K=int(raw_input())
left=0.0000000001
right=1000000001
while left+0.0000000001<right:
    mid=(left+right)/2
    cnt=0
    for l in L:
        cnt+=int(l/mid)
    if cnt>=K:
        left=mid
    else:
        right=mid
print left