Using *NODE PRINT Function for many points

Hello,
I would like to ask you one question regarding using the function *NODE PRINT in the input file.
I would like to extract the results for one additional RP ( NOT ONLY ONE NODE).
I modified the input file by writing at the end two additional lines:
*NODE PRINT, nset=RP, frequency=1
U2,RF2
*NODE PRINT, nset=RP2, frequency=1
U1
*End Step

So I would like to measure RF2 and U2 on the Reference point RP and U1 on the second Reference point U1
The code does not work. It seems that I am requesting the results on RP1 wrongly. 

Could you please advise me?
Best,