      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 Z(5).
      
      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.