Greg's marginal income tax rate is 30%. His property tax bill for 2018 was $12,000 and his total interest payments on his mortgage were $12,500. In addition, the property insurance cost $2,000 and the maintenance and repairs on the house was $3,000. Based on this information, what is Greg's total income tax shield (i.e. how much is Greg saving on his income taxes)? Assume he is not subject to the SALT (State and Local Tax) limitation.