auto save

1.py

+username="python"
+userpassword="1234"
+while True:
+    name=input("用户名：")
+    password=input("密码：")
+    if name==username and password==userpassword:
+        print("登陆成功！")
+        break
+    if name!=username:
+        print("用户名不存在")
+        continue
+    if password!=userpassword:  
+        print("密码不存在")
+print("欢迎来到贝尔编程")