View Compilation Error

0_0_34040854_22234.cpp: In function 'll g(int, int)':
0_0_34040854_22234.cpp:66:69: error: 'mod' was not declared in this scope
         ans = ans + 1ll * (pre[r] - pre[l-1]) * (m / l) * (n / l) % mod;
                                                                     ^
0_0_34040854_22234.cpp:68:18: error: 'mod' was not declared in this scope
     return ans % mod;
                  ^