I have a list of text data formatted as follows:

Drtyjtyjnt
11,825,222
Ftyryer
8,823,623
Strtrtuperd
8,542,448
Ts
7,153,156
Supd
7,122,304
Su.3
6,920,743
Supld
dddd
tgtgtg
Sd
April 1991
/////////////////////////
Freeeer
7,537,583
Dufdgnt
4,381,322
SioBup
3,010,937
S
2,238,608
Du
SuperM
Sup
August 1989
/////////////////////////
D
12,184,781
S
9,023,965
Fog
8,913,781
Supe
7,441,191
May 1991
/////////////////////////

I want to bookmark the last comma-separated value before each ///////////////////////// separator using Notepad++ regex. For example, in the list provided, the following lines should be bookmarked:

6,920,743
2,238,608
7,441,191

I have attempted to use the following regex patterns but they did not work:

(?-s)(d{1,3}(?:,d{3})+)(?=(?:(?!R/////////////////////////).)*R/////////////////////////)
(?s)(d{1,3}(?:,d{3})+)(?=(?:R(?!/////////////////////////).)*R/////////////////////////)

Could someone help identify what might be wrong with these regex patterns or provide a working solution?