save project

diy2.py

-a=0
+a=3
 u = "python"
 us = "123456"
 while True:
-    if a<0
+    if a>0:
         n = input("请输入用户名:")
         p = input("请输入密码:")
+        a-=1
         if n == u and p == us:
             print("登录成功!")
             break
         if u !=n:
             print("用户名错误!请重新输入")
-            a=a-1
             continue
         if us!= p:
             print("密码错误!请重新输入") 
-        if a==0:
-            exit
+    else:
+        exit()
 print("欢迎来到贝尔编程!")
\ No newline at end of file