The metric used in this competition is the **Mean Absolute Percentage Error**.
The mean absolute percentage error is often used for forecasting, and it describes how
accurate a forecast model is as a percentage.

\\[
     \frac{1}{n} \sum\_{i=1} \Bigg{|}
     \frac{Y\_i - 
          \widehat{Y}
           \_i}
          {Y\_i} \Bigg{|}
\\]