A soccer match is divided into two 45-minute halves, with additional time added at the discretion of the referee. A half-time interval of no more than 15 minutes separates the halves. Extra time is often determined by the referee based on how much time was lost due to substitutions and injuries. If scores are still level after extra time has been played, the match enters a penalty shootout phase. There is a lot of action throughout the game, but it can be divided into different phases: the buildup, the attack, the defense, and the end of the game. Each phase has its own responsibilities so that the game can be controlled by one team or the other. In the buildup phase, players move the ball around the field looking for open spaces. They pass the ball back and forth until someone finds an opportunity to shoot. A player with the ball is said to have possession of the game. In the attack phase, the player with the ball aims to put it in the net. He might do this by shooting or by scoring a direct free kick. The attack ends when the player with the ball is tackled or loses possession through a foul. In the defense phase, players protect the goal by using their bodies to block shots and passes. They also try to prevent opponents from getting the ball by stealing the ball themselves. This phase ends when the player with the ball is tackled or commits a serious foul.