The ratio of male to female among the 42 students in Class 1 is 1:1. At least how many students can be randomly selected to ensure that there are both male and female students?
六一班42名学生男女人数比为1：1，至少任意选取多少人才能保证男女生都有？
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">42 / 2</gadget>
<output>21</output>

<gadget id="calculator">21 + 1</gadget>
<output>22</output>

<result>22</result>