View Compilation Error

0_0_33927627_23011.cpp: In function 'bool operator<(const Q&, const Q&)':
0_0_33927627_23011.cpp:39:9: error: invalid use of non-static data member 'Q::l'
     int l, r, k;
         ^
0_0_33927627_23011.cpp:41:68: error: from this location
        return pos[a.l] == pos[b.l] ? a.r < b.r : pos[a.l] < pos[b, l];
                                                                    ^