Suppose you take out a 20-year mortgage for a house that costs $317760. Assume the following:

The annual interest rate on the mortgage is 4%.

The bank requires a minimum down payment of 18% at the time of the loan.

The annual property tax is 2.4% of the cost of the house.

The annual homeowner's insurance is 1.2% of the cost of the house.

The monthly PMI is $74

Your other long-term debts require payments of $775 per month.

If you make the minimum down payment, what is the minimum gross monthly salary you must earn in order to satisfy the 28% rule and the 36% rule simultaneously?