(and there shall not be taken into account under subsection (c)(2) any such contribution) to the extent such contribution does not exceed the excess (if any) of— (i) the aggregate amount of such distributions made during the 20-year period ending on the date of the contribution to which this subparagraph is applied, over (ii) the aggregate amount of contributions to which this subparagraph applies for all taxable years. (4) Qualified contributions For purposes of this subsection, the term qualified young saver contribution means a contribution by an individual (with respect to whom a young savers account is not established and maintained during the taxable year) to a young savers account established and maintained on behalf of another individual. . (b) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2017.