# challenge.py

```py
import gdb

class HelloPy(gdb.Command):
def __init__(self):
super(HelloPy, self).__init__('hello_py', gdb.COMMAND_USER)

def invoke(self, _unicode_args, _from_tty):

alf = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_+?{}'

# 0x555555555914 break

w = 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'
a = 0

while a < 58:
x = 0
while True:
ww = list(w)
ww[a] = alf[x]
gdb.execute(f"r <<< {''.join(ww)}")
for i in range(a):
gdb.execute('c')

if int(gdb.parse_and_eval("$rbx")) == int(gdb.parse_and_eval("$rax")):
w = ''.join(ww)
print(w)
a += 1
break
x += 1

HelloPy()
```


# FLAG

**`vsctf{1_b37_y0u_w1LL_n3v3r_u53_Func710n4L_C++_1n_ur_L1F3?}`**

Original writeup (https://github.com/acdwas/ctf/tree/master/2022/vsCTF%202022/rev/Functional%20CPP).