sum?=?0??????????????????????????sum?=?0
x?=?1????????????????????????????x?=?1
n?=?1????????????????????????????n?=?1
while?True:??????????????????????while?Ture:
????if?n?>?20:???????????????????????sum?=?sum?+?x
????????break????????????????????????x?=?x?*?2
????sum?=?sum?+?x????????????????????n?=?n?+?1
????x?=?x?*?2????????????????????????if?n?>?20:
????n?=?n?+?1????????????????????????????break
print?sum?????????????????????????print?sum