diff --git a/adventofcode/2025/day9/day9.py b/adventofcode/2025/day9/day9.py
new file mode 100644
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--- /dev/null
+++ b/adventofcode/2025/day9/day9.py
@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+import fileinput
+from sys import argv
+
+
+def area(a, b):
+    height = abs(a[1] - b[1]) + 1
+    width = abs(a[0] - b[0]) + 1
+    return height * width
+
+
+def test_area():
+    assert area((2, 5), (9, 7)) == 24, "Area between (2,5) and (9,7) should be 24"
+    assert area((7, 1), (11, 7)) == 35, "Area between (7,1) and (11,7) should be 35"
+    assert area((2, 5), (11, 1)) == 50, "Area between (2,5) and (11,1) should be 50"
+
+
+def generate_ppm(inp, scale=100):
+    """Generate a PPM file with scaled-down coordinates"""
+    coords = [(x // scale, y // scale) for x, y in inp]
+
+    max_x = max(x[0] for x in coords)
+    min_x = min(x[0] for x in coords)
+    max_y = max(x[1] for x in coords)
+    min_y = min(x[1] for x in coords)
+
+    height = max_y - min_y + 1
+    width = max_x - min_x + 1
+
+    print(f"Scaled dimensions: {width}x{height} (scale factor: {scale})")
+    print(f"Original dimensions: {max(x[0] for x in inp)}x{max(x[1] for x in inp)}")
+
+    arr = [[0] * (width) for _ in range(height)]
+    for x, y in coords:
+        if 0 <= y < height and 0 <= x < width:
+            arr[y][x] = 1
+
+    with open("test.ppm", "w") as f:
+        f.write(f"P3\n{width} {height}\n255\n")
+        for row in arr:
+            for cell in row:
+                f.write(f"{cell * 255} 0 0 ")
+            f.write("\n")
+
+    print("PPM file written to test.ppm")
+
+
+def main(inp):
+    coords = [tuple(map(int, x.split(","))) for x in inp]
+    max_area = 0
+    for a in coords:
+        for b in coords:
+            if a == b:
+                continue
+            max_area = max(max_area, area(a, b))
+    print("Part 1:", max_area)
+
+
+if __name__ == "__main__":
+    lines = [x.rstrip() for x in fileinput.input()]
+    # test_area()
+    main(lines)
+    # for vizualization
+    # generate_ppm([tuple(map(int, x.split(","))) for x in lines])
diff --git a/adventofcode/2025/day9/input.png b/adventofcode/2025/day9/input.png
new file mode 100644
index 0000000..2e22f85
Binary files /dev/null and b/adventofcode/2025/day9/input.png differ