diff --git a/2024/09/part1.py b/2024/09/part1.py
index 69fa3dc..c98cbcf 100644
--- a/2024/09/part1.py
+++ b/2024/09/part1.py
@@ -5,27 +5,24 @@ def load_disk_map(filename: str = "input") -> str:
 		data = fp.read().rstrip("\n")
 	return data
 
-def disk_map_to_blocks(disk_map: str) -> str:
-	blocks = ""
+def disk_map_to_blocks(disk_map: str) -> list:
+	blocks = []
 	for i, s in enumerate(disk_map):
 		# file
 		if i % 2 == 0:
 			ID = i // 2
-			blocks += int(s) * str(ID)
+			blocks += int(s) * [str(ID)]
 
 		# free space
 		else:
-			blocks += int(s) * "."
+			blocks += int(s) * ["."]
 
 	return blocks
 
-def move_ltr_to_empty_space(blocks: str) -> str:
+def move_ltr_to_empty_space(blocks: list) -> str:
 	left = 0
 	right = len(blocks) - 1
 
-
-	blocks = list(blocks)
-
 	while left < right:
 		if blocks[left] != ".":
 			left += 1
@@ -37,15 +34,15 @@ def move_ltr_to_empty_space(blocks: str) -> str:
 			blocks[right] = tmp
 		
 		if verbose:
-			print("".join(blocks))
+			print(blocks)
 
-	return "".join(blocks)
+	return blocks
 
 def checksum(blocks: str) -> int:
-	return sum([position * int(ID) for position, ID in enumerate(blocks.rstrip("."))])
+	return sum([position * int(ID) for position, ID in enumerate(blocks) if ID != "."])
 
 if __name__ == "__main__":
-	disk_map = load_disk_map("testinput")
+	disk_map = load_disk_map("input")
 	if verbose:
 		print("Disk map:")
 		print(disk_map)