Error Model Builder arcgis 10.5 in "Calcute value"

Question

both in mode 1 or mode 2 when executing "Calculate value" the model gives the same error. With the examples provided by "Arcgis Help" I have the same error.
my question because it gives me the error "The name contains invalid characters" ?. my current team is with windows 10 updated, if the platform is compatible for Windows 8 environment. However, the only time I could successfully execute this command is with the command "Replace", in this way ".replace ('-', '_')

modo 1

modo 2

resultado

Frankde_la_Barra · Answer

As I said before, in version 10.4 "% Variable%". replace ("-", "_") but version 10.5 does not work like this, it works as follows "% Variable%". replace ('-', '_') in arcgis 10.5

Frankde_la_Barra · Answer

As I said before, in version 10.4 "% Variable%". replace ("-", "_") but version 10.5 does not work like this, it works as follows "% Variable%". replace ('-', '_') in arcgis 10.5

DanPatterson_Retired · Answer

I suspect the issues come with the lack of specifically indicating that you would need an input oval that defines what 'A' and/or 'B' is

So in this example, nothing is going to work unless you have a 'Value'  oval