      IDENTIFICATION DIVISION.
      PROGRAM-ID. 135A.
      DATA DIVISION.
      WORKING-STORAGE SECTION.
      01 INP PIC X(100).
      01 A   PIC 9(10).
      01 B   PIC 9(10).
      01 SHO PIC 9(10).
      01 AMA PIC 9(1).
      01 ANS PIC 9(11).
      01 DISP PIC ZZZZZZZZZ9.

      PROCEDURE DIVISION.
      ACCEPT INP.
      UNSTRING INP DELIMITED BY " "
      INTO A B.
      COMPUTE ANS = A + B
      DIVIDE ANS BY 2 GIVING SHO REMAINDER AMA.
      MOVE SHO TO DISP.
      IF AMA = 1
      	DISPLAY "IMPOSSIBLE"
      ELSE
        DISPLAY DISP
      END-IF.
      STOP RUN.
      