Substitute each of the letters by a different decimal digit from 0 to 9 to satisfy this alphametic square root extraction problem. None of O and P can be 0.

                P I E R
  --------------------
√ O P E R A T O R |
   C T
------------
      B E R
      B A C
------------------
         E  P A T
         T  I A  I
----------------------
             P I  E O R
             P I  E O R
----------------------

Note: Try to derive a non computer assisted method, although computer program/spreadsheet solutions are welcome.