There are 13 teams participating in a basketball game. The competition is divided into two groups, the first group has 7 teams, and the second group has 6 teams. In each group, a single round-robin match is held first (that is, each team has to play one game with other teams in this group), and then the first place in the two groups will play another game to determine the champion and runner-up. Question: How many games are there in total?
有13个球队参加篮球比赛．比赛分两个组，第一组7个队，第二组6个队．各组内先进行单循环赛(即每队都要与本组中其他各队比赛一场)，然后由两组的第1名再比赛一场决定冠亚军．请问：一共需要比赛多少场？
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">6 * (5/2)</gadget>
<output>15</output>

<gadget id="calculator">7 - 1</gadget>
<output>6</output>

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

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<gadget id="calculator">15 + 21 + 1</gadget>
<output>37</output>

<result>37</result>