Find value in a value range in a split string

Hi guys,

I've got a split string as follows :

8;313;680;1182;1455;1782;2134;2496;2845;3100;3409;3792;4101;4518;4800;5069;5367;5700;5963;6275;6625;7056;7407;7700;7934;8198;8465;8838;9120;9338;9433;9675;9906;10201;10529;10770;11065;11276;11530;11736;11998;12304;
(42 segments in total)

These are row numbers in a sheet that determine a location.
Now on another sheet, I have numbers ranging between 8 and 12500.
What's the easiest way to put the right location next to the numbers in the second sheet?
For example, if the number in the second sheet is 1560, then that's in between 1455;1782 and therefore should be marked as location 5 (1455).
If the number in the second sheet is 3333, then that's in between3100;3409 and therefore should be marked as location 10 (3100)

Any suggestions on how to easily tackle this?
The split string is called "vestnum"

Thanks in advance