How to get DB ID when database in nomount state?

Issue below command in nomount state.
alter session set tracefile_identifier = DBID_TRACE;

alter system dump datafile 'C:\APP\ORACLE\ORADATA\TESTDB\SYSTEM01.DBF' block min 1 block max 10;

check the trace file

Start dump data block from file C:\APP\ORACLE\ORADATA\TESTDB\SYSTEM01.DBF minblk 1 maxblk 10
 V10 STYLE FILE HEADER:
Compatibility Vsn = 202375680=0xc100200
Db ID=2736190072=0xa316f278, Db Name='TESTDB'
Activation ID=0=0x0