View Compilation Error

0_0_33210820_9283.cpp: In function 'void add(int, int, int)':
0_0_33210820_9283.cpp:3:20: error: 'N' was not declared in this scope
     for(i = x; i < N; i += lowbit(i))
                    ^
0_0_33210820_9283.cpp:3:36: error: 'lowbit' was not declared in this scope
     for(i = x; i < N; i += lowbit(i))
                                    ^
0_0_33210820_9283.cpp:5:13: error: 'mat' was not declared in this scope
             mat[i][j] += d;
             ^
0_0_33210820_9283.cpp: At global scope:
0_0_33210820_9283.cpp:8:1: error: 'LL' does not name a type
 LL sum(int x, int y) {
 ^