diff --git a/InSange/DFS/2097 Valid Arrangement of Pairs.cpp b/InSange/DFS/2097 Valid Arrangement of Pairs.cpp
new file mode 100644
index 0000000..9f883e5
--- /dev/null
+++ b/InSange/DFS/2097 Valid Arrangement of Pairs.cpp	
@@ -0,0 +1,64 @@
+#include <unordered_map>
+#include <deque>
+#include <vector>
+
+using namespace std;
+
+class Solution {
+public:
+    unordered_map<int, deque<int>> nodes;
+    unordered_map<int, int> inDegree;
+    unordered_map<int, int> outDegree;
+
+    vector<int> result;
+
+    void DFS(int index)
+    {
+        while (!nodes[index].empty())
+        {
+            int nextNode = nodes[index].front();
+            nodes[index].pop_front();
+            DFS(nextNode);
+        }
+        result.push_back(index); // �ᱹ. ��� ������ �湮�ߴٸ�. �� ������ִ� ��忡 �湮�ߴٸ� ������ ��ΰ� �Ųٷ� �̾����� ��.
+    }
+
+    vector<vector<int>> validArrangement(vector<vector<int>>& pairs) {
+        for (const vector<int>& pair : pairs)
+        {
+            int depart = pair[0];
+            int dest = pair[1];
+
+            nodes[depart].push_back(dest);
+            inDegree[dest]++;
+            outDegree[depart]++;
+        }
+
+        int startNode = -1;
+
+        for (const auto& degree : outDegree)
+        {
+            int curNode = degree.first;
+            if (outDegree[curNode] == inDegree[curNode] + 1) // ���� ��忡�� ������� ���� ���� ������ ������ ���� + 1�� ���. �� ���� ���� ���� �ٽ� �ش� ��带 ���ľ� ��� ��带 �湮�� �� ����.
+            {
+                startNode = curNode;
+                break;
+            }
+        }
+
+        if (startNode == -1) // ��� ��带 �߰� ���ߴٸ� ��� ���� ���� �ϳ��� ����, �������� �����ϰ� ������ ��
+        {
+            startNode = pairs[0][0];
+        }
+
+        DFS(startNode);
+
+        vector<vector<int>> ans;
+        for (int i = result.size() - 1; i > 0; i--)
+        {
+            ans.push_back({ result[i], result[i - 1] }); // ������� �������� �Ųٷ� ����
+        }
+
+        return ans;
+    }
+};
\ No newline at end of file
diff --git a/InSange/README.md b/InSange/README.md
index 48462ff..b73134a 100644
--- a/InSange/README.md
+++ b/InSange/README.md
@@ -32,6 +32,7 @@
 | 28차시 | 2024.08.21 |  백트래킹 | [월드컵](https://www.acmicpc.net/problem/6987)  | [#28](https://github.com/AlgoLeadMe/AlgoLeadMe-8/pull/94)]
 | 29차시 | 2024.08.25 |  문자열 | [Find the Closest Palindrome](https://leetcode.com/problems/find-the-closest-palindrome/)  | [#29](https://github.com/AlgoLeadMe/AlgoLeadMe-8/pull/98)]
 | 30차시 | 2024.09.06 |  문자열 | [Delete Nodes From Linked List Present in Array](https://leetcode.com/problems/delete-nodes-from-linked-list-present-in-array/)  | [#30](https://github.com/AlgoLeadMe/AlgoLeadMe-8/pull/100)]
+| 31차시 | 2024.12.01 |  DFS | [Valid Arrangement of Pairs](https://leetcode.com/problems/valid-arrangement-of-pairs/)  | [#31](https://github.com/AlgoLeadMe/AlgoLeadMe-8/pull/101)]
 ---
 
 https://leetcode.com/problems/robot-collisions/