# The instances for the rack formulation have the following format:

N XXX   # (Number of distinct products)
R XXX   # (Number of racks in warehouse)
O XXX   # (Number of outstanding orders)

RS XXX  # (Number of shelves in a rack, i.e. number of distinct products that fit
           in a rack)

Racks
 Index Prod Qty ...
 ...

# In the racks section of the instance file, we show in each row:
#  - The index of that rack (from 0 in the first row to R-1 in the last row)
#  - Then we include RS times in each row:
#     - The product identifier held in one of the shelves in that rack (from 0 to N-1)
#     - The quantity of that product stored in that rack shelf.
#
# Example:
# 
# R  2
# RS 3
# 
# Racks
#   0  4  3  8  1 23  1
#   1 96  2 10  4 61  2
#
# Above there are two racks (0 and 1, each containing 3 distinct products).
# Rack 0 has 3 units of product 4, 1 unit of product 8 and 1 unit of product 23
# Rack 1 has 2 units of product 96, 4 units of product 10 and 2 units of product 61


Orders
 Index Qty Prod Prod Prod ...
 ...


# In the orders section of the instance file, we show in each row:
#  - The index of that order (from 0 in the first row to O-1 in the last row)
#  - The number of items Qty requested in that order
#  - Then we include Qty product identifiers.
#    - Notice that if there are repeated products in an order the same
#      identifier can appear more than once
#
# Example:
#
# O 2
#
# Orders
# 0 3 7 15 15
# 1 4 9 9 11 11
# 
# In the example above, there are 2 outstanding orders.
# Order 0 requires 3 products, 1 unit of product 7 and 2 units of product 15
# Order 1 requires 4 products, 2 units of product 9 and 2 units of product 11