4 sticks are needed to place a square, 7 sticks are needed to place 2 squares, and at least how many sticks are needed to place 5 squares.
摆一个正方形需要4根小棒，摆2个正方形需要7根小棒，摆5个正方形至少需要多少根小棒．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">15 + 1</gadget>
<output>16</output>

<result>16</result>