Team A and Team B each have 5 players. At the beginning of the game, every two players shake hands once. How many times will they shake hands in total?
甲乙两队各有5名球员，比赛开始每2人之间握一次手，一共要握多少次手．
<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<result>25</result>