View Compilation Error

0_0_37119446_25885.cpp: In function 'int main()':
0_0_37119446_25885.cpp:72:49: error: invalid operands of types '__gnu_cxx::__promote_2<int, int, double, double>::__type {aka double}' and 'const ll {aka const long long int}' to binary 'operator%'
                          * (pow(2,num_a)-1))) % mod;
                                                 ^