From the 30 natural numbers 1, 2, 3, ..., 30, at least how many different numbers must be taken out to ensure that one of them must be a multiple of 5.
从1，2，3，…，30这30个自然数中，至少要取出多少个不同的数，才能保证其中一定有一个数是5的倍数．
<gadget id="calculator">24 + 1</gadget>
<output>25</output>

<result>25</result>