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day03-2.py

@@ -155,8 +155,9 @@ def main():
     lines = load_input(3)
     # Input is lines of periods (.), numbers (0-9), and symbols 
     # (anything that isn't a period or number)
-    # Any number adjacent (horizontally, vertically, diagonally)
-    # to a symbol is a part number. Get the sum of the part numbers.
+    # Any asterisk (*) adjacent to exactly two numbers is a gear;
+    # its value is the product of the two numbers.
+    # Get the sum of all of the gear values.
     max_len = len(lines[0]) # all lines are the same length
     for j, line in enumerate(lines):
         i = 0