* Copy the main file `exercise_basic_2p.cc` and rename it to `exercise_basic_2pni.cc`
* In `exercise_basic_2pni.cc`, include the header `injection2pniproblem.hh` instead of `injection2pproblem.hh`.
* In `exercise_basic_2pni.cc`, change `Injection2pCCTypeTag` to `Injection2pNICCTypeTag` in the line `using TypeTag = Properties::TTag::Injection2pNICCTypeTag;`
* In `exercise_basic_2pni.cc`, change `Injection2pCC` to `Injection2pNICC` in the line `using TypeTag = Properties::TTag::Injection2pNICC;`
* Add a new executable in `CMakeLists.txt` by adding the lines