diff --git a/2020/day03/day03.hs b/2020/day03/day03.hs
new file mode 100644
index 0000000..38ba0f9
--- /dev/null
+++ b/2020/day03/day03.hs
@@ -0,0 +1,23 @@
+main :: IO ()
+main = do
+  input <- map (concat . repeat) . lines <$> readFile "input"
+  print $ day3 input ((3,1),0)
+  let slopes = [((1,1),0),((3,1),0),((5,1),0),((7,1),0),((1,2),0)]
+  print $ product $ map (day3 input) slopes
+
+type Slope = ((Int, Int), Int)
+
+day3 :: [String] -> Slope -> Int
+day3 input slope = a
+  where
+    (_, a) = day3rec (input, 0) slope
+
+day3rec :: ([String], Int) -> Slope -> ([String], Int)
+day3rec (t:ts, acc) ((x, y), l) =
+  day3rec
+    ( drop y (t : ts)
+    , if t !! (l * x) == '.'
+        then acc
+        else succ acc)
+    ((x, y), succ l)
+day3rec x _ = x
diff --git a/2020/day03/input b/2020/day03/input
new file mode 100644
index 0000000..ffaf42b
--- /dev/null
+++ b/2020/day03/input
@@ -0,0 +1,323 @@
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diff --git a/2020/day03/testinput b/2020/day03/testinput
new file mode 100644
index 0000000..7e88cdc
--- /dev/null
+++ b/2020/day03/testinput
@@ -0,0 +1,11 @@
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