The gift tax amount (it means the gift tax amount calculated relating
to the donated property at the time of its donation), pertaining to donated
property which was added to inherited property provided for in the provisions
of Article 13, shall be deducted from the inheritance tax amount calculated:
Provided, That in a case where, with respect to donated property being
added to the taxable amount of inheritance taxes, the gift tax fails to
be levied, owing to the expiration of the period, under the provisions of