I'll get you the materials necessary for a planetary shield. You should have everything within a month at most.
Meanwhile, you need to begin a survey of every system along the blast front. There may be other worlds in need of umbrellas.
No problem. That's only what, four million cubic light-years of space?
Sure... if you're rounding Pi down to three. Please don't make me add "rounding Pi down to three" to your list of crimes.