Using warnings and checking your error log would have given you the answer instantly.

$ perl -e'use warnings; if ("Schvalit_vse" == "Schvalit_vse") {}'
Argument "Schvalit_vse" isn't numeric in numeric eq (==) at -e line 1.
Argument "Schvalit_vse" isn't numeric in numeric eq (==) at -e line 1.
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