diff --git a/BaekJoon/4195/yerin.py b/BaekJoon/4195/yerin.py
new file mode 100644
index 0000000..c9cce8c
--- /dev/null
+++ b/BaekJoon/4195/yerin.py
@@ -0,0 +1,48 @@
+import sys
+from collections import defaultdict
+
+
+def find(parent, x):
+    if parent[x] != x:
+        parent[x] = find(parent, parent[x])
+    return parent[x]
+
+
+def union(parent, size, a, b):
+    root_a = find(parent, a)
+    root_b = find(parent, b)
+
+    if root_a != root_b:
+        if size[root_a] < size[root_b]:
+            parent[root_a] = root_b
+            size[root_b] += size[root_a]
+        else:
+            parent[root_b] = root_a
+            size[root_a] += size[root_b]
+
+    return size[find(parent, a)]
+
+
+def main():
+    input = sys.stdin.readline
+    t = int(input().strip())
+
+    for _ in range(t):
+        f = int(input().strip())
+        parent = {}
+        size = {}
+
+        for _ in range(f):
+            a, b = input().strip().split()
+            if a not in parent:
+                parent[a] = a
+                size[a] = 1
+            if b not in parent:
+                parent[b] = b
+                size[b] = 1
+
+            print(union(parent, size, a, b))
+
+
+if __name__ == "__main__":
+    main()