Four. Because if the Pope doesn't let them change the light bulb, all light itself will die.
How many Feeneyites does it take to change a light bulb?
None; all you need is a light bulb change of desire.
How many sedevacantists does it take to change a light bulb?
What bulb? There hasn't been one since 1958.
One night I had a wondrous dream,
One set of footprints there were seen,
The footprints of my precious Lord,
But mine were not along the shore.
But then some stranger prints appeared,
And I asked the Lord, "What have we here?"
Those prints are large and round and neat,
"But Lord, they are too big for feet."
"My child," He said in somber tones,
"For miles I carried you alone.
I challenged you to walk in faith,
But you refused and made me wait."
"You disobeyed, you would not grow,
The walk of faith, you would not know,
So I got tired, I got fed up,
And there I dropped you on your butt."
"Because in life, there comes a time,
When one must fight, and one must climb,
When one must rise and take a stand,
Or leave their butt prints in the sand."
~Author Unknown~