Converting a value from text to integer not allowing to assign result variable

Good morning

When I try to convert a value from a text to an integer, it does not allow me to select a variable to store the result of the conversion in. This problem completely stops me from continuing my work. The value I'm trying to convert is from a SharePoint lookup column (for some reason the lookup column returns the id as a text) which I need to query a different list for more information on the selected item.