I have to update the Value in field in Order object using field update in workflow Rule

Updated field value should be:

Account JDE Shipto number- YYMMDDHHmmSS 

like this format

for that i am using Formula field editor to populate the Value 


[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/oz7Wb.png

**`but it is showing error, what i have to give in the Datetimevalue(expression) please anyone guide me for the Answer`**