10  DIM A$[255],X$[5]
20  FILES B4
25  READ #1,1
30  READ #1;A$,A$,A$
40  FOR X=1 TO 500
50  CONVERT X TO X$
60  UPDATE #1;X$
70  READ #1;A$,A$,A$,A$,A$
90  NEXT X
99  END 
