def main():
    N, M = map(int, input().split())
    A = list(map(int, input().split()))

    sum_ = A[0]
    for idx in range(1, N):
        if A[idx] <= sum_ // idx:
            sum_ += A[idx]
        else:
            try:
                A[idx+1] += A[idx] - sum_ // idx
            except IndexError:
                pass
            sum_ += sum_ // idx

    print((sum_ // idx)//M)


if __name__ == "__main__":
    main()