diff --git a/day3/part1/main.d b/day3/part1/main.d
index df48eda..4e3dc00 100644
--- a/day3/part1/main.d
+++ b/day3/part1/main.d
@@ -5,16 +5,12 @@ void main()
     File("input", "r").byLineCopy.array.countTrees(3, 1).writeln;
 }
 
-ulong countTrees(const char[][] input, int angleX, int angleY)
+auto countTrees(const char[][] input, int angleX, int angleY)
 in(input.length > 0)
 {
     immutable width = input[0].length;
-    size_t x = 0;
-    return input.stride(angleY).map!((row) {
-        immutable result = row[x];
-        x = (x + angleX) % width;
-        return result;
-    })
+    return input.stride(angleY).enumerate
+        .map!(row => row.value[(row.index * angleX) % width])
         .filter!(pos => pos == '#')
         .count;
 }
diff --git a/day3/part2/main.d b/day3/part2/main.d
index 088c826..1d793d7 100644
--- a/day3/part2/main.d
+++ b/day3/part2/main.d
@@ -17,12 +17,8 @@ auto countTrees(const char[][] input, int angleX, int angleY)
 in(input.length > 0)
 {
     immutable width = input[0].length;
-    size_t x = 0;
-    return input.stride(angleY).map!((row) {
-        immutable result = row[x];
-        x = (x + angleX) % width;
-        return result;
-    })
+    return input.stride(angleY).enumerate
+        .map!(row => row.value[(row.index * angleX) % width])
         .filter!(pos => pos == '#')
         .count;
 }