Coming off their win against the Steelers, the Chiefs went on the road for an AFC West rivalry match against the San Diego Chargers. In the first quarter the Chiefs trailed early as QB Philip Rivers got a 19-yard touchdown pass to TE Antonio Gates. The Chiefs would reply to tie the game with QB Matt Cassel making a 7-yard touchdown pass to WR Chris Chambers, until they fell back again with RB LaDainian Tomlinson getting a 1-yard touchdown run, then Rivers hooking up with Gates again on a 15-yard touchdown pass, then DB Paul Oliver returned a fumble 40 yards for a touchdown. In the third quarter the Chiefs' struggle continued as RB LaDainian Tomlinson got a 3-yard touchdown run. They tried to come back with RB Jamaal Charles getting a 2-yard touchdown run, but the Chargers would pull away with kicker Nate Kaeding making a 55-yard field goal. In the fourth quarter the problem got worse when a penalty on Matt Cassel was enforced in the end zone for a safety, giving the Chargers 2 points. The final score was made when Kaeding booted a 23-yard field goal.

Based on the above article, answer a question. How many touchdowns happened in the first half?
5