The outermost layer of the Go board can hold 19 pieces on each side. How many pieces can be placed on the outermost layer?
围棋盘的最外层每边能放19个棋子，最外层一共可以摆放多少棋子？
<gadget id="calculator">19 * 4</gadget>
<output>76</output>

<gadget id="calculator">76 - 4</gadget>
<output>72</output>

<result>72</result>