diff --git a/3/engine.py b/3/engine.py
index 6f19640..b282ab2 100644
--- a/3/engine.py
+++ b/3/engine.py
@@ -18,8 +18,8 @@ def parse_input(input_data: str) -> dict:
     # convert input into a 2d array for easier parsing
     field = [line for line in input_data.split("\n")]
 
-    # get coordinates of numbers
-    nums = {
+    # create a dictionary of all symbols and their coordinates
+    symbols = {
         (i, char): []
         for i in range(140)
         for char in range(140)
@@ -28,16 +28,18 @@ def parse_input(input_data: str) -> dict:
 
     # for each row in field
     for i, row in enumerate(field):
-        # for each number in row
+        # for each number in row create a dictionary of any number with coords
         for n in re.finditer(r"\d+", row):
-            edge = {
+            numbers = {
                 (i, char)
                 for i in (i - 1, i, i + 1)
                 for char in range(n.start() - 1, n.end() + 1)
             }
-            for o in edge & nums.keys():
-                nums[o].append(int(n.group()))
-    return nums
+
+            # append each number to the list of numbers
+            for o in numbers & symbols.keys():
+                symbols[o].append(int(n.group()))
+    return symbols
 
 
 if __name__ == "__main__":