n = int(input())
l = list(map(int, input().split()))
k = int(input())

def f(x):
    ret = 0
    for i in range(n):
        ret += l[i] // x
    return ret

ok = 0
ng = 10 ** 9 + 1

for i in range(100):
    m = (ok + ng) / 2
    if f(m) >= k:
        ok = m
    else:
        ng = m

print(ok)