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+--- Day 3: Toboggan Trajectory ---
+
+With the toboggan login problems resolved, you set off toward the airport. While travel by toboggan
+might be easy, it's certainly not safe: there's very minimal steering and the area is covered in
+trees. You'll need to see which angles will take you near the fewest trees.
+
+Due to the local geology, trees in this area only grow on exact integer coordinates in a grid. You
+make a map (your puzzle input) of the open squares (.) and trees (#) you can see. For example:
+
+..##....... #...#...#.. .#....#..#. ..#.#...#.# .#...##..#. ..#.##..... .#.#.#....# .#........#
+#.##...#... #...##....# .#..#...#.#
+
+These aren't the only trees, though; due to something you read about once involving arboreal
+genetics and biome stability, the same pattern repeats to the right many times:
+
+..##.........##.........##.........##.........##.........##....... --->
+#...#...#..#...#...#..#...#...#..#...#...#..#...#...#..#...#...#..
+.#....#..#..#....#..#..#....#..#..#....#..#..#....#..#..#....#..#.
+..#.#...#.#..#.#...#.#..#.#...#.#..#.#...#.#..#.#...#.#..#.#...#.#
+.#...##..#..#...##..#..#...##..#..#...##..#..#...##..#..#...##..#.
+..#.##.......#.##.......#.##.......#.##.......#.##.......#.##..... --->
+.#.#.#....#.#.#.#....#.#.#.#....#.#.#.#....#.#.#.#....#.#.#.#....#
+.#........#.#........#.#........#.#........#.#........#.#........#
+#.##...#...#.##...#...#.##...#...#.##...#...#.##...#...#.##...#...
+#...##....##...##....##...##....##...##....##...##....##...##....#
+.#..#...#.#.#..#...#.#.#..#...#.#.#..#...#.#.#..#...#.#.#..#...#.# --->
+
+You start on the open square (.) in the top-left corner and need to reach the bottom (below the
+bottom-most row on your map).
+
+The toboggan can only follow a few specific slopes (you opted for a cheaper model that prefers
+rational numbers); start by counting all the trees you would encounter for the slope
+right 3, down 1:
+
+From your starting position at the top-left, check the position that is right 3 and down 1. Then,
+check the position that is right 3 and down 1 from there, and so on until you go past the bottom of
+the map.
+
+The locations you'd check in the above example are marked here with O where there was
+an open square and X where there was a tree:
+
+..##.........##.........##.........##.........##.........##....... --->
+#..O#...#..#...#...#..#...#...#..#...#...#..#...#...#..#...#...#..
+.#....X..#..#....#..#..#....#..#..#....#..#..#....#..#..#....#..#.
+..#.#...#O#..#.#...#.#..#.#...#.#..#.#...#.#..#.#...#.#..#.#...#.#
+.#...##..#..X...##..#..#...##..#..#...##..#..#...##..#..#...##..#.
+..#.##.......#.X#.......#.##.......#.##.......#.##.......#.##..... --->
+.#.#.#....#.#.#.#.O..#.#.#.#....#.#.#.#....#.#.#.#....#.#.#.#....#
+.#........#.#........X.#........#.#........#.#........#.#........#
+#.##...#...#.##...#...#.X#...#...#.##...#...#.##...#...#.##...#...
+#...##....##...##....##...#X....##...##....##...##....##...##....#
+.#..#...#.#.#..#...#.#.#..#...X.#.#..#...#.#.#..#...#.#.#..#...#.# --->
+
+In this example, traversing the map using this slope would cause you to encounter 7
+trees.
+
+Starting at the top-left corner of your map and following a slope of right 3 and down 1,
+how many trees would you encounter?
+
+