ONE
HASH(0x622430)
HASH(0x622430)
a
a
TWO
a
a a b b
Use of uninitialized value in concatenation (.) or string at /home/smk/prog/pl/interesting.pl line 10.

Use of uninitialized value in concatenation (.) or string at /home/smk/prog/pl/interesting.pl line 11.

THREE
HASH(0x622430)
HASH(0x622430)
a
a