Erastoten sieve

MODULE erastoten;
FROM InOut IMPORT WriteString, WriteLn, WriteCard;
FROM FIO IMPORT File, Open, Close, RdCard, EOF;
CONST
   n = 1000;
   n2 = 1000;
TYPE
    CL = SET OF [2..n];
    INTR = [0..n2];
VAR
   primes : CL;
   arr : ARRAY INTR OF CARDINAL;
   f : File;
   i : CARDINAL;

PROCEDURE ES(): CL;
//functional PROCEDURE for erastoten sieve
VAR
   i, next : CARDINAL;
   sieve, prime : CL;
BEGIN
     sieve := CL{2..n};
     prime := CL{};
     next := 2;
     REPEAT
           WHILE NOT (next IN sieve) DO
                 INC(next)
           END;
           INCL(prime, next);
           i := next;
           WHILE i <= n DO
             EXCL(sieve,i);
             i := i + next
           END
     UNTIL sieve = CL{};
     RETURN prime;
END ES;

BEGIN
     //Enter name of file!
     f:= Open('name.txt');
     i := 0;
     EOF := FALSE;
     WHILE NOT EOF DO
         INC(i);
         arr[i] := RdCard(f);
     END;
     Close(f);
     primes := ES();
     FOR i := 1 TO n2 DO
       IF arr[i] IN primes THEN
         WriteString('Number ');
         WriteCard(arr[i],0);
         WriteString(' from input list is a prime number!')
         WriteLn
       END
     END;
END erastoten.