diff --git a/3/rucksack.py b/3/rucksack.py
new file mode 100644
index 0000000..52e27e1
--- /dev/null
+++ b/3/rucksack.py
@@ -0,0 +1,44 @@
+import string
+
+from aocd.models import Puzzle
+from aocd import submit
+
+def eval_priority(rucksack: str) -> int:
+    '''
+        evaluates the priority of a duplicate item
+    '''
+
+    # create a map of priority values
+    priorities = dict(zip(string.ascii_letters, range(1,53)))
+
+    # slize rucksack into compartments
+    size = len(rucksack)
+    a,b = rucksack[:size//2], rucksack[size//2:]
+
+    # find the duplicate item
+    duplicate = ''.join(
+        set(a).intersection(b)
+    )
+
+    # return the priority
+    return priorities[duplicate]
+
+def parse_input(data: list) -> list:
+    '''
+        parses the input data and generates a list
+    '''
+    # split move set into a list of rounds
+    return [ move for move in data.split('\n')]
+
+if __name__ == "__main__":
+    # get puzzle and parse data
+    puzzle = Puzzle(year=2022, day=3)
+    supplies = parse_input(puzzle.input_data)
+
+    # part a: determine the priority of all duplicate items
+    answer = sum([eval_priority(rucksack) for rucksack in supplies])
+    print(f'sum of priorities of all duplicate items: {answer}')
+    submit(answer, part='a', day=3, year=2022)
+
+    # part b:
+    #submit(total, part='b', day=3, year=2022)