N = int(input())
stickList = list(map(int,input().split()))
K = int(input())

def countCuttedSticks(stickList, cutLength):
    count = 0
    for stick in stickList:
        count += stick // cutLength
    
    return count
    
def main():
    low = 0
    high = max(stickList)
    if countCuttedSticks(stickList, high) == K:
        print(high)
    else:
        previousAns = -1
        for i in range(100):
            ans = (low + high) / 2
            if countCuttedSticks(stickList, ans) >= K: # 本数を少なくするために切る長さを長くする
                low = ans
            else: # 本数を多くするために切る長さを短くする
                high = ans
            
        print(ans)

if __name__ == '__main__':
    main()