In the Karatsuba algorithm to multiply two numbers, we divide each number into two. For example:

```
x= 1234
y= 2456
```

Then a = 12, b = 34, c = 24, d = 56

What happens if the digits in each number are not even or equal? What is the rule by dividing it into two parts?

Example:

```
x = 12345
y = 2478
```

or

```
x = 12456778
y = 241
```

Please help.