View Compilation Error

0_0_37879301_12956.cpp: In function 'void solve()':
0_0_37879301_12956.cpp:83:28: error: invalid operands of types '__gnu_cxx::__promote_2<int, long long int, double, double>::__type {aka double}' and 'const int' to binary 'operator%'
     cout << (pow(2,ans)-1)%mod << endl;
                            ^