A classroom is 8m long, 6m wide, and 4m high. The area of doors, windows and blackboards is 25.4 square meters. Now the roof and four walls of the classroom need to be painted. If the labor cost is 4 yuan per square meter, how much will it cost to paint the classroom?
一间教室长8m，宽6m，高4m，门窗和黑板面积为25.4平方米，现要粉刷教室的屋顶和四面墙壁，如果每平方米要4元人工费，粉刷这个教室要花多少元？
<gadget id="calculator">8 * 6</gadget>
<output>48</output>

<gadget id="calculator">8 * 4</gadget>
<output>32</output>

<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">32 + 24</gadget>
<output>56</output>

<gadget id="calculator">56 * 2</gadget>
<output>112</output>

<gadget id="calculator">112 - 25.4</gadget>
<output>86.6</output>

<gadget id="calculator">48 + 86.6</gadget>
<output>134.6</output>

<gadget id="calculator">134.6 * 4</gadget>
<output>538.4</output>

<result>538.4</result>