/in/foo.cc: In function 'int main()':
/in/foo.cc:20:23: error: invalid operands of types '__gnu_cxx::__promote_2<int, long long int, double, double>::__type {aka double}' and 'long long int' to binary 'operator%'
  r=(x%n+(m%n*pow(10,k)%n)%n)%n;
          ~~~~~~~~~~~~~^~