Error and Bug!

[QuestionPython]

$ gcc main.c -o main -O3 -w

$ time ./main

0. piece is Serkan
1. piece is Korkut
2. piece is 21832132
3. piece is smks
*** Error in `./main': realloc(): invalid next size: 0x0000563969674510 ***
======= Backtrace: =========
/usr/lib/libc.so.6(+0x722ab)[0x7fd605be82ab]
/usr/lib/libc.so.6(+0x7890e)[0x7fd605bee90e]
/usr/lib/libc.so.6(+0x7b91c)[0x7fd605bf191c]
/usr/lib/libc.so.6(realloc+0x159)[0x7fd605bf2c09]
./main(+0x124e)[0x563968ecb24e]
./main(+0x7a3)[0x563968eca7a3]
/usr/lib/libc.so.6(__libc_start_main+0xf1)[0x7fd605b96511]
./main(+0x9ea)[0x563968eca9ea]
======= Memory map: ========
563968eca000-563968ecc000 r-xp 00000000 08:11 2755444                    /home/guest/Projects/C-Performance/try2/main
5639690cb000-5639690cc000 r--p 00001000 08:11 2755444                    /home/guest/Projects/C-Performance/try2/main
5639690cc000-5639690cd000 rw-p 00002000 08:11 2755444                    /home/guest/Projects/C-Performance/try2/main
563969674000-563969695000 rw-p 00000000 00:00 0                          [heap]
7fd600000000-7fd600021000 rw-p 00000000 00:00 0 
7fd600021000-7fd604000000 ---p 00000000 00:00 0 
7fd60595f000-7fd605975000 r-xp 00000000 08:01 6426218                    /usr/lib/libgcc_s.so.1
7fd605975000-7fd605b74000 ---p 00016000 08:01 6426218                    /usr/lib/libgcc_s.so.1
7fd605b74000-7fd605b75000 r--p 00015000 08:01 6426218                    /usr/lib/libgcc_s.so.1
7fd605b75000-7fd605b76000 rw-p 00016000 08:01 6426218                    /usr/lib/libgcc_s.so.1
7fd605b76000-7fd605d11000 r-xp 00000000 08:01 6424699                    /usr/lib/libc-2.25.so
7fd605d11000-7fd605f10000 ---p 0019b000 08:01 6424699                    /usr/lib/libc-2.25.so
7fd605f10000-7fd605f14000 r--p 0019a000 08:01 6424699                    /usr/lib/libc-2.25.so
7fd605f14000-7fd605f16000 rw-p 0019e000 08:01 6424699                    /usr/lib/libc-2.25.so
7fd605f16000-7fd605f1a000 rw-p 00000000 00:00 0 
7fd605f1a000-7fd605f3d000 r-xp 00000000 08:01 6424700                    /usr/lib/ld-2.25.so
7fd6060fb000-7fd6060fd000 rw-p 00000000 00:00 0 
7fd60613b000-7fd60613c000 rw-p 00000000 00:00 0 
7fd60613c000-7fd60613d000 r--p 00022000 08:01 6424700                    /usr/lib/ld-2.25.so
7fd60613d000-7fd60613e000 rw-p 00023000 08:01 6424700                    /usr/lib/ld-2.25.so
7fd60613e000-7fd60613f000 rw-p 00000000 00:00 0 
7ffd0f8c0000-7ffd0f8e1000 rw-p 00000000 00:00 0                          [stack]
7ffd0f92b000-7ffd0f92d000 r--p 00000000 00:00 0                          [vvar]
7ffd0f92d000-7ffd0f92f000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]
Aborted (core dumped)

real	0m0.014s
user	0m0.003s
sys	0m0.000s

Please Fix this. 👍