		IDENTIFICATION DIVISION.
        PROGRAM-ID. AtCoder.
      
        ENVIRONMENT DIVISION.
      
        DATA DIVISION.
        WORKING-STORAGE SECTION.
        01 INP PIC X(100).
        01 A PIC 9(15).
        01 B PIC 9(15).
        01 C PIC ZZZZZZZZZZZZZZZ.
      	01 t PIC 9(15).
	    01 temp1 PIC 9(15).
        01 temp2 PIC 9(15).
        01 N PIC 9(15).
      
        PROCEDURE DIVISION.
      	MAIN.
			ACCEPT INP.
        	PERFORM VARYING temp1 FROM 1 BY 1
            UNTIL INP(temp1:1) = SPACE
        	END-PERFORM.
        	SUBTRACT 1 FROM temp1.
        	MOVE INP(1:temp1) TO A.
        	ADD 2 TO temp1.
        	PERFORM VARYING temp2 FROM temp1 BY 1
            UNTIL INP(temp2:1) = SPACE
        	END-PERFORM.
        	COMPUTE N = temp2 - temp1.
        	MOVE INP(temp1:N) TO B.
      		COMPUTE C = A - B - B.
			IF A > B + B THEN
				DISPLAY C
			ELSE 
				DISPLAY "0"
			END-IF.
		STOP RUN.