IDENTIFICATION DIVISION.
PROGRAM-ID. ADD.
ENVIRONMENT DIVISION.
DATA DIVISION.
WORKING-STORAGE SECTION.
77 Idx PICTURE 9(4).
77 Sum PICTURE 9(6).
77 X   PICTURE X.
PROCEDURE DIVISION.
BEGIN.
    ACCEPT X.
    MOVE ZERO TO IDX.
    MOVE ZERO TO SUM.
    PERFORM ADD UNTTI TDX = 1001.