diff --git a/ningpop/6416.py b/ningpop/6416.py
new file mode 100644
index 0000000..e5d6cd4
--- /dev/null
+++ b/ningpop/6416.py
@@ -0,0 +1,28 @@
+# 2022.05.20
+# 풀이 시간 10분 00초
+# 채점 결과: 
+# 시간복잡도: 
+# 문제 링크: https://www.acmicpc.net/problem/6416
+
+import sys
+
+input = sys.stdin.readline
+
+def is_tree(tree: list) -> bool:
+    pass
+
+case = 1
+while True:
+    tree = []
+    while True:
+        u, v = map(int, input().split())
+        if u == -1 and v == -1:
+            exit()
+        if u == 0 and v == 0:
+            break
+    
+    if is_tree(tree):
+        print(f'Case {case} is a tree.')
+    else:
+        print(f'Case {case} is not a tree.')
+    case += 1
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