A deck of playing cards (excluding the big and little ghost kings) has 4 suits, and each suit has 13 cards. Now shuffle the playing cards, then at least how many cards must be drawn from it to ensure that 4 cards are of the same suit.
一副扑克牌(除去大，小鬼王)，有4种花色，每种花色都有13张牌．现在把扑克牌洗匀，那么至少要从中抽出多少张牌，才能保证有4张牌是同一花色．
<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<gadget id="calculator">12 + 1</gadget>
<output>13</output>

<result>13</result>