hi I'm new to java and having trouble solving this. 

```
void setNumber(int inputNumber)
{
    int currentNumber = inputNumber;
    int previousNumber = ??????????

}

```

so if inputNumber is " 2 " , then currentNumber should be " 2 "
and I want to change inputNumber to something else but I want previousNumber to be " 2 " 
and on and on, previousNumber to have one step before currentNumber's new value. 
how can I do this? 

Thanks!