auto save

a.py

 username="python"
 username="python"
 userword="123456"
 userword="123456"
+while True:
+    a=input("请输入用户名:")
+    b=input("请输入密码:")
+    if a=="python"and b=="123456":
+        print("输入正确")
+        break
+    else:
+        if a!="python":
+            print("用户名错误")
+            continue
+        else:
+            print("密码错误")
+print("欢迎您!")
+
+