KK heads up after an A flops

[Sandwich]

7 left, 10+1 NL SNG on Party Poker, blinds are 50/100.

I have 725 chips.

I have K [img]/images/graemlins/diamond.gif[/img] K [img]/images/graemlins/club.gif[/img] in MP.

UTG limps, EP (who has me covered by 50 chips) raises to 100.

I make it 300. UTG folds. EP calls.

Flop comes A [img]/images/graemlins/diamond.gif[/img] 4 [img]/images/graemlins/club.gif[/img] 9 [img]/images/graemlins/spade.gif[/img]


EP pushes his remaining stack all in.

What's your move?

Me? (in white)
<font color="white"> I joined EP all in. EP flipped AJ of hearts and ends up beating me with a pair of aces.</font>