The length of a circular runway is 40 meters. Xiao Dong and Xiao Ming set off at the same point on the runway in opposite directions at the same time. Xiao Dong runs 6 meters per second, and Xiao Ming runs 4 meters per second. Then, except for the first departure, how many times did the two meet on the way and then meet at the original starting point.
一条环形跑道的长是40米，小东和小明在跑道上同一点沿相反方向同时出发，小东每秒跑6米，小明每秒跑4米．那么，除第一次出发外，两人在中途相遇了多少次后又相遇在原出发点．
<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<gadget id="calculator">6 - 4</gadget>
<output>2</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">40 / 8</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<result>4</result>