@mssrleong
Just go ahead and indicate the box 1 $$ amount as the RMD.
Even for regularly-paid pensions, there is an RMD, but the pension plan has already pre-determined and used the correct amount. Thus, your full gross in box 1 of that 1099-R is the RMD.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*