Q: This task involves creating answers to complex questions, from a given passage. Answering these questions, typically involve understanding multiple sentences. Make sure that your answer has the same type as the "answer type" mentioned in input. The provided "answer type" can be of any of the following types: "span", "date", "number". A "span" answer is a continuous phrase taken directly from the passage or question. You can directly copy-paste the text from the passage or the question for span type answers. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words. A "number" type answer can include a digit specifying an actual value. For "date" type answers, use DD MM YYYY format e.g. 11 Jan 1992. If full date is not available in the passage you can write partial date such as 1992 or Jan 1992. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words.
Passage: The Chargers defeated the Kansas City Chiefs 37-20 and started the season with a 3-1 record for the second consecutive year. San Diego forced the Chiefs into six turnovers, and they led 20-0 in the second quarter. Rivers completed 18 of 23 passes for 209 yards and two touchdown passes, but threw one interception in the red zone. Jackie Battle started at running back instead of Mathews. Battle was in 27 plays compared to Mathews' 21, and he had 15 carries for 39 yards with a team-high four catches for 42 yards. Most of Mathews work was in the fourth quarter when San Diego's victory was mostly already decided. U-T San Diego wrote that Mathews would have been expected to start were it not for his fumble against Atlanta the prior week. Nick Novak filled in for kicker Nate Kaeding, who was out with a groin injury, and made all three of his field goals.
Question: How many passes did Rivers complete?
Answer type: Number
A:
18.