Dan and Maureen file a joint income tax return for 2018. They have two dependent children, ages 7 and 9. Together they earn wages of $830,000. They also receive taxable interest income of $8,000 and interest on City of Los Angeles bonds of $78,000. During 2018, they received a state income tax refund of $3,000 relating to their 2017 state income tax return on which they itemized deductions. Their expenses for the year consist of the following:

Home mortgage interest (on acquisition debt)

$19,000

Interest on credit cards

2,000

Real property taxes

8,300

Cash contributions

75,000

State income taxes withheld

48,000

Calculate Dan and Maureen's tentative minimum tax liability assuming an AMT exemption amount of $109,400, before any phase-outs. Show your calculations.