NL100 river valuebet 2p IP when flush hits?

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Just a few hands played on the table.

Party Poker - No Limit Hold'em Cash Game - $0.50/$1 Blinds - 6 Players - (LegoPoker HH Converter)

SB: $99.10
BB: $49.27
UTG: $27.28
MP: $23.14
CO: $162.88
Hero (BTN): $108.83

Preflop: Hero is dealt A[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/heart.gif[/img] (6 Players)
UTG calls $1.00, 2 folds, <font color="red">Hero raises to $4.50</font>, SB calls $4.00, BB folds, UTG calls $3.50

Flop: ($14.50) K 2 3[img]/images/graemlins/spade.gif[/img] (3 Players)
SB checks, UTG checks, <font color="red">Hero bets $10.00</font>, SB calls $10.00, UTG calls $10.00

Turn: ($44.50) K 2 3[img]/images/graemlins/spade.gif[/img] 7 (3 Players)
SB checks, UTG checks, <font color="red">Hero bets $33.50</font>, SB calls $33.50, UTG folds

River: ($111.50) K 2 3[img]/images/graemlins/spade.gif[/img] 7 A (2 Players)
SB checks, <font color="red">Hero ???</font>

$51 left