suppose to have the following:

data DB;
input ID :$20. Admission :date09. Discharge :date09. Index1;
format Admission date9. Discharge date9.;
cards;
0001 13JAN2017 25JAN2017 0 
0001 22FEB2018 03MAR2018 0 
0001 30JAN2019 04MAR2019 0 
0001 30JAN2019 04MAR2019 1 
0001 25DEC2020 02JAN2021 0 
0002 15JAN2014 29JAN2014 1 
0002 01FEB2015 10FEB2015 0 
0002 01FEB2015 10FEB2015 0 
0003 22MAR2019 23MAR2019 1 
0003 22MAR2019 23MAR2019 0
0003 02JUL2019 28AUG2019 0
0004 01SEP2022 15SEP2022 1
0004 02DEC2023 05DEC2023 1
;run;

Is there a way to get the following? In other words I need to remove duplicated rows (identical admission-discharge date) and retain the inly one where Index1 = 1. I tried with proc sort to order by the date and the Index1 (descending) without success. Thank you in advance!

data DB1;
input ID :$20. Admission :date09. Discharge :date09. Index1;
format Admission date9. Discharge date9.;
cards;
0001 13JAN2017 25JAN2017 0 
0001 22FEB2018 03MAR2018 0 
0001 30JAN2019 04MAR2019 1 
0001 25DEC2020 02JAN2021 0 
0002 15JAN2014 29JAN2014 1 
0002 01FEB2015 10FEB2015 0 
0003 22MAR2019 23MAR2019 1   
0003 02JUL2019 28AUG2019 0              
0004 01SEP2022 15SEP2022 1            
0004 02DEC2023 05DEC2023 1
;run;