N = int(input()) L = list(map(int, input().split())) K = int(input()) def calc_bou(N, L, K): low = 0 high = max(L) for _ in range(70): mid = (low + high) / 2 cnt = 0 for i in L: cnt += i // mid if cnt < K: high = mid else: low = mid return low print(calc_bou(N, L, K))