import sys

def solve():
    def check(mid):
        cnt = 0

        for i in range(N):
            cnt += int(L[i] // mid)

            if cnt >= K:
                return True

        return False
    
    N = int(input())
    L = [int(i) for i in input().split()]
    K = int(input())

    btm = 0
    top = sum(L) / K

    for i in range(50):
        mid = (top + btm) / 2

        if check(mid):
            btm = mid
        else:
            top = mid

    print(btm)

if __name__ == '__main__':
    solve()