The 8-1 Bengals traveled to Arizona to face the 7-2 Cardinals and former Bengals #1 overall draft pick Carson Palmer. In the first quarter, the Bengals would strike first as Dalton found Tyler Eifert on a 3-yard touchdown pass to give them a 7-0 lead for the only score of the period. In the second quarter, the Cardinals would tie the game when Palmer found Darren Fells from 18 yards out to tie things up at 7. The Bengals would retake the lead as Jeremy Hill ran into the endzone from 2 yards out to give them a 14-7 lead at halftime. In the 3rd quarter, it was all Cardinals, as Carson Palmer found J.J Nelson for a 64-yard touchdown to tie the game at 14. Arizona would take their first lead of the game as Palmer found John Brown from 18 yards out to give them a 21-14 lead. The Cardinals would extend the lead as Palmer found David Johnson from 16 yards out to extend the lead to 28-14.  In the fourth quarter, the Bengals would cut into the lead as Hill ran in his second touchdown of the night, this one from 1 yard out, to cut the deficit to 28-21. After a Dalton fumble, Chandler Catanzaro would extend the Arizona lead to 31-21. However, the Bengals would make the game close once again, as Eifert caught his second touchdown of the night, cutting the lead to 31-28. Cincinnati would tie the game 31-31 on a Mike Nugent field goal. However, Palmer and the Cardinals offense went right down the field to get into the field goal range. The most notable part of this drive, and, perhaps, the game, was an unsportsmanlike conduct penalty by Bengals defensive tackle Domata Peko. The penalty was for mimicking the count during the huddle. The penalty made the field goal easier, and Catanzaro nailed the game winner from 32 yards out as time expired to end the game. With the loss, the Bengals fell to 8-2. The loss also dropped them to 0-4 all time against the Cardinals on the road, and 0-3 all time against them in Arizona.
Question: How many yards was the longest touchdown pass of the first half?
Answer: 18