REM Rosetta Code problem: https://rosettacode.org/wiki/A+B
REM by Jjuanhdez, 06/2022

10  LET C = 0
    LET D = 0
    PRINT "Enter an integer: "
    INPUT A
    IF A < 0 THEN LET C = A * -1
    PRINT "Enter other integer: "
    INPUT B
    IF B < 0 THEN LET D = B * -1
    IF C > 1000 THEN GOTO 60
    IF D > 1000 THEN GOTO 60
50  PRINT "Their sum is ", A + B
    GOTO 70
60  PRINT "Both integers must be in the range [-1000..1000] - try again."
    GOTO 10
70  END