签到

int __fastcall main(int argc, const char **argv, const char **envp)
{
  int v4; // [rsp+Ch] [rbp-34h] BYREF
  char s[48]; // [rsp+10h] [rbp-30h] BYREF  
  strcpy(s, "flag{c0ngr@tul@ti0n_f0r_luck_numb3r}");
  v4 = 0;
  __isoc99_scanf(&unk_2004, &v4);
  if ( v4 == 7 )
    return puts(s);
  else
    return puts("sorry!");
}

flag

flag{c0ngr@tul@ti0n_f0r_luck_numb3r}