View Compilation Error

0_0_34200025_30087.cpp: In function 'll q_pow(ll, ll, ll)':
0_0_34200025_30087.cpp:27:18: error: invalid operands of types '__gnu_cxx::__promote_2<long long int, long long int, double, double>::__type {aka double}' and 'll {aka long long int}' to binary 'operator%'
     res=pow(a,b)%mod;
                  ^