When students plant trees, one more person per group of 2, 3 more per group of 4, and 4 more per group of 5. At least how many students will plant trees?
同学们去植树，每2人一组多1人，每4人一组多3人，每5人一组多4人，至少有多少同学去植树？
<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<result>19</result>