A total of 14 teams participate in an international football invitational tournament. The game adopts a single round-robin system. How many games will be held in total?
一次国际足球邀请赛，共有14个队参加，比赛采用单循环制，共要举行多少场比赛．
<gadget id="calculator">14 - 1</gadget>
<output>13</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<gadget id="calculator">13 * 7</gadget>
<output>91</output>

<result>91</result>