Road Service — JOISC 2018 Day 2 Problem 2

Download the six official inputs, 01.txt through 06.txt.
Submit six separate answer files:

Input     Answer file     Number of roads to output
01.txt    01.txt                     4
02.txt    02.txt                   100
03.txt    03.txt                   300
04.txt    04.txt                   100
05.txt    05.txt                   100
06.txt    06.txt                   300

Each answer uses the statement's output format: K pairs of city numbers.
Each input is scored independently using its original optimization formula.
Scores use the platform’s normal rounding, with an integer final total.
This may differ from the original statement’s final-only rounding.

Original task: Japanese Committee for the International Olympiad in Informatics.
https://www2.ioi-jp.org/camp/2018/2018-sp-tasks/index.html
License: Creative Commons Attribution-ShareAlike 4.0 International.
The six input files are unchanged.
