View Compilation Error

0_0_30502861_10374.cpp: In function 'int main()':
0_0_30502861_10374.cpp:57:34: error: invalid operands of types '__gnu_cxx::__promote_2<int, long long int, double, double>::__type {aka double}' and 'const long long int' to binary 'operator%'
                 ans=4*pow(3,p-1)%mod;
                                  ^
0_0_30502861_10374.cpp:61:32: error: invalid operands of types '__gnu_cxx::__promote_2<int, long long int, double, double>::__type {aka double}' and 'const long long int' to binary 'operator%'
                 ans=2*pow(3,p)%mod;
                                ^
0_0_30502861_10374.cpp:65:32: error: invalid operands of types '__gnu_cxx::__promote_2<int, long long int, double, double>::__type {aka double}' and 'const long long int' to binary 'operator%'
                 ans=1*pow(3,p)%mod;
                                ^