diff --git a/libs/P_C.py b/libs/S_D.py
similarity index 100%
rename from libs/P_C.py
rename to libs/S_D.py
diff --git a/libs/__init__.py b/libs/__init__.py
index c976dad..b39f7fc 100644
--- a/libs/__init__.py
+++ b/libs/__init__.py
@@ -6,7 +6,7 @@ mail: 3695888@qq.com
 import libs.Game_threads
 
 # import in this forder
-import libs.P_C
+import libs.S_D
 import libs.main
 import libs.tools
 import libs.loads
diff --git a/test.py b/test.py
index e64057b..702937c 100644
--- a/test.py
+++ b/test.py
@@ -12,9 +12,9 @@ B = [0.245, -7, ["N", "kg"], ["m", "s"]]
 print("A = " , A)
 print("B = " , B)
 
-C = libs.P_C.S_N_M(A, B)
-D = libs.P_C.S_N_D(A, B)
-E = libs.P_C.S_N_D(C, B)
+C = libs.S_D.S_N_M(A, B)
+D = libs.S_D.S_N_D(A, B)
+E = libs.S_D.S_N_D(C, B)
 
 print("A × B = " , C)
 print("A ÷ B = " , D)