There are 54 cards in a deck of poker, ask: at least how many cards can be drawn from it to ensure that there are cards of four suits.
一副扑克牌有54张，问：至少从中摸出多少张牌才能保证：四种花色的牌都有．
<gadget id="calculator">13 * 3</gadget>
<output>39</output>

<gadget id="calculator">39 + 2 + 1</gadget>
<output>42</output>

<result>42</result>