import sys input = sys.stdin.readline def get_num_tree(length): ans = sum(int(tree / length) for tree in L) return ans n = int(input()) L = tuple(map(int, input().split())) k = int(input()) l = 0 r = max(L) + 1 # while r - l >= 10 ** (-9): # mid = (l + r) / 2 # if get_num_tree(mid) >= k: # l = mid # else: # r = mid for _ in range(50): mid = (l + r) / 2 if get_num_tree(mid) >= k: l = mid else: r = mid print(l)