A certain unit holds a party. There are 100 people present at the meeting. Every two people shake hands once. How many handshakes are there in total?
某单位召开一次联欢大会，到会100人，每两人握一次手，一共握多少次手．
<gadget id="calculator">100 - 1</gadget>
<output>99</output>

<gadget id="calculator">100 / 2</gadget>
<output>50</output>

<gadget id="calculator">99 * 50</gadget>
<output>4_950</output>

<result>4_950</result>