deck of poker (excluding King and King), in order to make the cards drawn have 4 suits, then at least how many cards must be drawn.
一副扑克(除去大小王)，要使摸到的牌4种花色都有，那么至少要摸多少张牌．
<gadget id="calculator">13 * 3</gadget>
<output>39</output>

<gadget id="calculator">39 + 1</gadget>
<output>40</output>

<result>40</result>