#define ull unsigned long long

就这个玩意儿，为什么一直报错呢？

2.cpp: In function ‘int main()’:
2.cpp:3:13: error: expected primary-expression before ‘unsigned’
    3 | #define ull unsigned long long
      |             ^~~~~~~~
2.cpp:32:12: note: in expansion of macro ‘ull’
   32 |      cout<<ull(-n)<<endl;
      |            ^~~

求解答，没懂它要我加什么