Complete the function that takes two numbers as input, num and nth and return the nth digit of num (counting from right to left).
- If num is negative, ignore its sign and treat it as a positive value
- If nth is not positive, return -1
- Keep in mind that 42 = 00042. This means that findDigit(42, 5) would return 0
5673, 4 --> 5
129, 2 --> 2
-2825, 3 --> 8
-456, 4 --> 0
0, 20 --> 0
65, 0 --> -1
24, -8 --> -1