Дан файл, строки которого могут содержать и числа, и слова. Сформировать другой файл, содержащий только числа

CLS
DIM L AS STRING
OPEN "a.txt" FOR INPUT AS #1
OPEN "b.txt" FOR OUTPUT AS #2
DO WHILE NOT EOF(1)
LINE INPUT #1, Stri$
IF (Stri$ >= "0") AND (Stri$ <= "9") THEN
PRINT #2, Stri$
END IF
LOOP
CLOSE
END

OPEN "a.txt" FOR INPUT AS #1
OPEN "b.txt" FOR OUTPUT AS #2
  DO WHILE NOT EOF(1)
  LINE INPUT #1, stri$
  dlina = LEN(stri$)
  novST$ = ""
    FOR i = 1 TO dlina
    simvol$ = MID$(stri$, i, 1)
    IF simvol$ >= "0" AND simvol$ <= "9" THEN novST$ = novST$ + simvol$
    NEXT i
  PRINT #2, novST$
  LOOP
CLOSE

CLS
OPEN "1.txt" FOR INPUT AS #1
OPEN "2.txt" FOR OUTPUT AS #2
 
CONST z = "1234567890"
CONST p = " "
DIM stri AS STRING
DIM novs AS STRING
DIM simv AS STRING
 
DO
   LINE INPUT #1, stri
   dlina = LEN(stri)
   novs = ""
 
   FOR i = 1 TO dlina
      simv = MID$(stri, i, 1)
      IF INSTR(z, simv) THEN
         novs = novs + simv
      ELSEIF RIGHT$(novs, 1) <> p THEN
         novs = novs + p
      END IF
   NEXT
 
   PRINT #2, novs
LOOP UNTIL EOF(1)
CLOSE