N = int(input()) L = list(map(int,input().split())) K = int(input()) ok = 0 ng = 10**9 def is_ok(x): cnt = 0 for i in range(N): num = L[i] // x cnt += num if cnt >= K: return 1 return 0 while ng - ok > 10**(-10): mid = (ng + ok) / 2 if is_ok(mid): ok = mid else: ng = mid # print(ok,ng) print(ok)