On October 22, the Chiefs returned to Arrowhead to face division rivals, the San Diego Chargers.  The game was broadcast on CBS at noon Kansas City time. Trent Green had been ruled out to start in the game, but has been cleared by doctors to begin practicing with the squad.  Ronnie Cruz, the Chiefs' only fullback, is out for the year following an unspecified knee injury.  Tight end Kris Wilson took over for Cruz.  The Chiefs also signed fullback Greg Hanoian in the days before the game to add depth to the position. The game started with the Chiefs forcing turnovers on San Diego's first four possessions.  Damon Huard later converted turnovers with two touchdown passes.  Jared Allen forced a fumble from quarterback Philip Rivers, recovered by Tamba Hali.  The Chiefs took advantage of the turnover by scoring a touchdown with Eddie Kennison, making the lead 14-0.  The Chargers would kick a field goal and the Chiefs would respond with a 15-yard field goal extending the lead to 20-3.  The Chargers would not go into halftime with a 17-point deficit, so they kicked another field goal with 5&#160;minutes to halftime. The game was tied for the rest of the fourth quarter until 33&#160;seconds remained when Damon Huard led the Chiefs to a 52-yard gain with 3 passes&#8212;two of them to Tony Gonzalez for 37&#160;yards. The gain by Gonzalez set up for a game-winning field goal by kicker Lawrence Tynes. With 11&#160;seconds left in the game, with the Chiefs trying to avoid overtime, Tynes connected on a career long 53-yard kick which later gave the Chiefs the victory, 30-27.

Answer this question based on the article: How many points ahead were the Chiefs ahead of the Chargers after the 15-yard field goal?
17