library(data.table)

# Input data files are available in the "../input/" directory.

# Read in only required columns and force to numeric to ensure that subsequent 
# aggregation when calculating medians works
train <- fread('../input/train.csv', 
               select = c('Producto_ID', 'Agencia_ID', 'Ruta_SAK', 'Cliente_ID', 'Demanda_uni_equil'),
               colClasses=c(Producto_ID="numeric", Ruta_SAK="numeric", Agencia_ID="numeric", Cliente_ID="numeric",Demanda_uni_equil="numeric"))