diff --git a/day-23/input/coco.txt b/day-23/input/coco.txt
new file mode 100644
index 00000000..6215abc0
--- /dev/null
+++ b/day-23/input/coco.txt
@@ -0,0 +1 @@
+326519478
\ No newline at end of file
diff --git a/day-23/part-1/coco.py b/day-23/part-1/coco.py
new file mode 100644
index 00000000..9da44669
--- /dev/null
+++ b/day-23/part-1/coco.py
@@ -0,0 +1,37 @@
+from tool.runners.python import SubmissionPy
+
+
+class CocoSubmission(SubmissionPy):
+    def run(self, s):
+        """
+        :param s: input in string format
+        :return: solution flag
+        """
+        # Your code goes here
+        cups = [int(x) for x in list(s.strip())]
+        N = len(cups)
+        position = 0
+        for k in range(100):
+            item = cups[position]
+            removed = [cups[(position + k) % N] for k in range(1, 4)]
+            remaining = [cups[(position + k) % N] for k in range(4, len(cups) + 1)]
+            destination_value = (item - 2) % N + 1
+            while destination_value in removed:
+                destination_value = (destination_value - 2) % N + 1
+            index = remaining.index(destination_value)
+            cups = remaining[:index+1] + removed + remaining[index+1:]
+            position = (cups.index(item) + 1) % N
+        
+        index_one = cups.index(1)
+        return "".join(str(cups[k % N]) for k in range(index_one + 1, index_one + len(cups)))
+
+def test_coco():
+    """
+    Run `python -m pytest ./day-23/part-1/coco.py` to test the submission.
+    """
+    assert (
+        CocoSubmission().run(
+            """389125467""".strip()
+        )
+        == "67384529"
+    )
diff --git a/day-23/part-2/coco.py b/day-23/part-2/coco.py
new file mode 100644
index 00000000..390ea0ae
--- /dev/null
+++ b/day-23/part-2/coco.py
@@ -0,0 +1,64 @@
+from tool.runners.python import SubmissionPy
+
+class LinkedListNode:
+    def __init__(self, value) -> None:
+        self.value = value
+        self.next = None
+
+
+class CocoSubmission(SubmissionPy):
+
+    def run(self, s):
+        """
+        :param s: input in string format
+        :return: solution flag
+        """
+        # Your code goes here
+        inputs = [int(x) for x in list(s.strip())]
+        cups = list(range(1, int(1e6+1)))
+        cups[:len(inputs)] = inputs
+        
+        N = len(cups)
+
+        # init linked list
+        nodes = [LinkedListNode(value=cups[0])]
+        for i in range(1, len(cups)):
+            node = LinkedListNode(value=cups[i])
+            nodes.append(node)
+            nodes[i-1].next = node
+        nodes[-1].next = nodes[0]  # loop over beginning
+
+        value_to_node = {
+            node.value: node for node in nodes
+        }
+
+        node = nodes[0]
+        for _ in (range(int(1e7))):
+            next_three = [node.next, node.next.next, node.next.next.next]
+            node.next = node.next.next.next.next  # 4th
+
+            removed_values = {n.value for n in next_three}
+            destination_value = (node.value - 2) % N + 1
+            while destination_value in removed_values:
+                destination_value = (destination_value - 2) % N + 1
+
+            node_dest = value_to_node[destination_value]
+            next_tmp = node_dest.next 
+            node_dest.next = next_three[0]
+            next_three[2].next = next_tmp
+            node = node.next
+
+        node_one = [n for n in nodes if n.value == 1][0]
+        return node_one.next.value * node_one.next.next.value
+
+
+def test_coco():
+    """
+    Run `python -m pytest ./day-23/part-1/coco.py` to test the submission.
+    """
+    assert (
+            CocoSubmission().run(
+                """389125467""".strip()
+            )
+            == 149245887792
+    )