Except as provided in paragraph (2), the aggregate amount of the deductions allowed by sections
243
(a)(1),
244
(a), and subsection (a) or (b) of section
245 shall not exceed the percentage determined under paragraph (3) of the taxable income computed without regard to the deductions allowed by sections
172,
199,
243
(a)(1),
244
(a), subsection (a) or (b) of section
245, and 247, without regard to any adjustment under section
1059, and without regard to any capital loss carryback to the taxable year under section
1212
(a)(1).