The toy factory wants to manufacture a batch of intellectual toys. It is planned to produce 45 per day and complete in 19 days. The actual production is 57 per day, how many days can it be completed in advance?
玩具厂要制造一批智力玩具．计划每天生产45个，19天完成．实际每天生产57个，可以提前几天完成？
<gadget id="calculator">19 / 57</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">45 * (1/3)</gadget>
<output>15</output>

<gadget id="calculator">19 - 15</gadget>
<output>4</output>

<result>4</result>