Hoe can I flag the last record who has AVALC = 'Y' record prior to this AVALC='N' record.

[SerenaJJ]

Hi, I need to flag the last AVALC = 'Y' record prior to this AVALC='N' record. For example,

for the following dataset, I need to flag the third A record and second B subjid . Thank you so much

data have;
input usubjid $ ADY AVALC $;
datalines;
A 15 N
A 36 N
A 57 Y
A 60 N
A 61  Y
A 62 N
A 63 Y
A 64 Y
A 65 Y
B 15 Y
B 36 Y
B 57 N
B 58 N
B 60 Y
;
run;

[SerenaJJ]

How*