View Compilation Error

0_0_36633351_30961.cpp:11:29: error: 'inv' was not declared in this scope
 const ll inv2 = inv(2ll, mod);
                             ^
0_0_36633351_30961.cpp:12:29: error: 'inv' was not declared in this scope
 const ll inv6 = inv(6ll, mod);
                             ^