The ratio of odd to even numbers

Odd Numbers: such as 1,3,5,7,9

Even Number: such as 0,2,4,6,8

0: 0 odd number(s)，3 even number(s)

1: 1 odd number(s)，2 even number(s)

2: 2 odd number(s)，1 even number(s)

3: 3 odd number(s)，0 even number(s)