TASK DEFINITION: In this task, you're given a sentence and your task is to generate a simplified sentence that focuses on lexical paraphrasing from the original sentence given in the input.
PROBLEM: the fourth and fifth digits designate the number of the urban area -lrb- in a district-free city -rrb- or the district -lrb- in a city with districts -rrb-.

SOLUTION: the fourth and fifth numbers are the amount of the urban area -lrb- in a district-free city -rrb- or the district -lrb- in a city with districts -rrb-.

PROBLEM: cogeneration -lrb- also combined heat and power , chp -rrb- is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat.

SOLUTION: cogeneration is a combination of heart and power to simultaneously generate both electricity and useful heat.

PROBLEM: the only known communal roost contained only four individuals.

SOLUTION:
only communal known contained roost four individuals.