How to use values ​​with java scanner without storing them in memory?

Question

Java

Hello, I solve Java problems and among them there is one type of problems in which you need to keep within a very limited amount of memory (~ 20MB).
I read data from stdin or from a file with a scanner, almost all the data read is used once, there are those whose values ​​I overwrite, they are all ints.
So, can I not save these one-time ints in memory (I mean after I used it) and indicate for others that when the value changes, the variable does not change the reference to a new memory cell, but changes the value in the current one, as in increments?