View Compilation Error

0_0_39536527_13608.cpp:8:1: error: 'LL' does not name a type; did you mean 'ULL'?
    8 | LL fn[MAXN+1];
      | ^~
      | ULL
0_0_39536527_13608.cpp: In function 'void setfn()':
0_0_39536527_13608.cpp:14:5: error: 'fn' was not declared in this scope
   14 |     fn[0] = 0;
      |     ^~
0_0_39536527_13608.cpp: In function 'int main()':
0_0_39536527_13608.cpp:35:26: error: 'fn' was not declared in this scope; did you mean 'n'?
   35 |         printf("%lld\n", fn[b - a + 1]);
      |                          ^~
      |                          n