      IDENTIFICATION DIVISION.
      PROGRAM-ID. 121A.
      DATA DIVISION.
      WORKING-STORAGE SECTION.
      01 INP PIC X(100).
      01 BH PIC 9(2).
      01 BW PIC 9(2).
      01 LH PIC 9(2).
      01 LW PIC 9(2).
      01 ANS PIC 9(5).
      01 ANSS PIC ZZZZ9.
      
      PROCEDURE DIVISION.
 
      ACCEPT INP.
      UNSTRING INP DELIMITED BY " "
	  INTO BH BW.

      ACCEPT INP.
      UNSTRING INP DELIMITED BY " "
	  INTO LH LW.

      COMPUTE ANS = ( BH - LH ) * ( BW - LW ).
	  MOVE ANS TO ANSS.   
      DISPLAY ANSS.
      STOP RUN.
