There are 6 cylindrical columns in front of a certain auditorium. The circumference of the bottom of the columns is 2.5 meters and the height is 6 meters. If these columns are to be painted (on average, 2 square meters can be painted per liter of paint), how many liters of paint will be used in total?
某礼堂前面有6根圆柱形状的立柱，立柱的底面周长2.5米，高6米．如果要给这些立柱漆上油漆(平均每升油漆可漆2平方米)，一共要用油漆多少升？
<gadget id="calculator">2.5 * 6</gadget>
<output>15</output>

<gadget id="calculator">15 * 6</gadget>
<output>90</output>

<gadget id="calculator">90 / 2</gadget>
<output>45</output>

<result>45</result>