diff --git a/src/main/scala/de.qwertyuiop.aoc/2021/day1.scala b/src/main/scala/de.qwertyuiop.aoc/2021/day01.scala
similarity index 100%
rename from src/main/scala/de.qwertyuiop.aoc/2021/day1.scala
rename to src/main/scala/de.qwertyuiop.aoc/2021/day01.scala
diff --git a/src/main/scala/de.qwertyuiop.aoc/2021/day2.scala b/src/main/scala/de.qwertyuiop.aoc/2021/day02.scala
similarity index 100%
rename from src/main/scala/de.qwertyuiop.aoc/2021/day2.scala
rename to src/main/scala/de.qwertyuiop.aoc/2021/day02.scala
diff --git a/src/main/scala/de.qwertyuiop.aoc/2021/day3.scala b/src/main/scala/de.qwertyuiop.aoc/2021/day03.scala
similarity index 100%
rename from src/main/scala/de.qwertyuiop.aoc/2021/day3.scala
rename to src/main/scala/de.qwertyuiop.aoc/2021/day03.scala
diff --git a/src/main/scala/de.qwertyuiop.aoc/2021/day4.scala b/src/main/scala/de.qwertyuiop.aoc/2021/day04.scala
similarity index 100%
rename from src/main/scala/de.qwertyuiop.aoc/2021/day4.scala
rename to src/main/scala/de.qwertyuiop.aoc/2021/day04.scala
diff --git a/src/main/scala/de.qwertyuiop.aoc/2021/day5.scala b/src/main/scala/de.qwertyuiop.aoc/2021/day05.scala
similarity index 100%
rename from src/main/scala/de.qwertyuiop.aoc/2021/day5.scala
rename to src/main/scala/de.qwertyuiop.aoc/2021/day05.scala
diff --git a/src/main/scala/de.qwertyuiop.aoc/2021/day6.scala b/src/main/scala/de.qwertyuiop.aoc/2021/day06.scala
similarity index 100%
rename from src/main/scala/de.qwertyuiop.aoc/2021/day6.scala
rename to src/main/scala/de.qwertyuiop.aoc/2021/day06.scala
diff --git a/src/main/scala/de.qwertyuiop.aoc/2021/day7.scala b/src/main/scala/de.qwertyuiop.aoc/2021/day07.scala
similarity index 100%
rename from src/main/scala/de.qwertyuiop.aoc/2021/day7.scala
rename to src/main/scala/de.qwertyuiop.aoc/2021/day07.scala
diff --git a/src/main/scala/de.qwertyuiop.aoc/2021/day8.scala b/src/main/scala/de.qwertyuiop.aoc/2021/day08.scala
similarity index 100%
rename from src/main/scala/de.qwertyuiop.aoc/2021/day8.scala
rename to src/main/scala/de.qwertyuiop.aoc/2021/day08.scala
diff --git a/src/main/scala/de.qwertyuiop.aoc/2021/day9.scala b/src/main/scala/de.qwertyuiop.aoc/2021/day09.scala
similarity index 100%
rename from src/main/scala/de.qwertyuiop.aoc/2021/day9.scala
rename to src/main/scala/de.qwertyuiop.aoc/2021/day09.scala