In the 2008 World Cup football group match, there are four teams: China, Brazil, Turkey, and Costa Rica. Every two teams compete once. How many games will the four teams compete in total?
2008年世界杯足球小组赛，有中国、巴西、土耳其、哥斯达黎加四个队，每两个队比一次，4支队伍共比多少场．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<result>6</result>