I couldn't input NRA, letters instead numbers in the SSN box in form IT-201. How can I type NRA in the SSN box

I plan to filea Tax return married filing separately with my NRA spouse and the software dosen't allow to enter NRA in the SSN field but the other accountants do. I know I can print it out and file by mail. But I don't want to leave the SSN field blank. How can I type NRA in the SSN field?