A company has interest expenses totaling $=$ $$722$ MM$,$ for which they pay $7\%/$annum to their lender. Last year, the company paid $$827$ MM in tax, based on earnings before taxes of $$4,135$M; what amount of additional taxes would the co$.$ pay if they were all equity$-$financed $($i$.$e$.,$ no debt$)$ and what is the PV of tax shield $($assume all metrics stay constant in perpetuity$)?$