def Check(x):
    cnt = 0
    for i in range(N):
        cnt += L[i] // x
    if cnt >= K:
        return True
    else:
        return False

N = int(input())
L = list(map(int,input().split()))
K = int(input())
ok = 0
ng = max(L) + 1
for _ in range(100):
    x = (ok + ng) / 2
    if Check(x):
        ok = x
    else:
        ng = x
print(ok)