<P> In mathematics, parity is the property of an integer's inclusion in one of two categories: even or odd . An integer is even if it is evenly divisible by two and odd if it is not even . For example, 6 is even because there is no remainder when dividing it by 2 . By contrast, 3, 5, 7, 21 leave a remainder of 1 when divided by 2 . Examples of even numbers include − 4, 0, 8, and 1738 . In particular, zero is an even number . Some examples of odd numbers are − 5, 3, 9, and 73 . </P> <P> A formal definition of an even number is that it is an integer of the form n = 2k, where k is an integer; it can then be shown that an odd number is an integer of the form n = 2k + 1 . It is important to realize that the above definition of parity applies only to integer numbers, hence it cannot be applied to numbers like 1 / 2, 4.201 . See the section "Higher mathematics" below for some extensions of the notion of parity to a larger class of "numbers" or in other more general settings . </P>

Given an integer n find the difference between the sums of its even and odd digits