PokerStars No-Limit Hold'em, $0.50 BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP ($53.15)
CO ($138.15)
Button ($11.75)
SB ($77.10)
Hero ($96.35)
UTG ($26.45)

Preflop: Hero is BB with A, J.
UTG calls $0.50, 4 folds, Hero raises to $2, UTG calls $1.50.

Flop: ($4.25) J, 7, 9 (2 players)
Hero bets $3, UTG raises to $6, Hero calls $3.

Turn: ($16.25) 3 (2 players)
Hero checks, UTG checks.

River: ($16.25) T (2 players)
Hero checks, UTG bets $18.45 (All-In), Hero ???

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Villian is an unknown shortstack.

What's' your river move here, and how was the rest of the hand played?