To profile, use
```
-stack build --executable-profiling --library-profiling --ghc-options="-fprof-auto -rtsopts"
+stack build --executable-profiling --library-profiling --ghc-options="-fprof-auto -rtsopts" advent01
```
then run with
```
-stack exec -- advent01 +RTS -p -hy
+stack exec --profile -- advent01 +RTS -p -hy
```
Generate the profile graph with
```