def get_inputs( filename ):
    """
    The input file has intructions in each line with a command and a value. 
    This function returns the instructions as a list of lists.
    """
    with open( filename, 'r') as input_file:
        inputs = [ [ item[:1], int(item[1:]) ] for 
                     item in input_file.read().splitlines() ]
    return inputs