PROBLEM STATEMENT
Let us introduce a new operation called double xor, and use the operator ^^ to denote it.  For two 
integers A and B, A ^^ B is calculated as follows.  Take the decimal representations of A and B.  
If they have different lengths, prepend the shorter one with leading zeros until they both have 
the same length.  Then, label the digits of A as a1, a2, �c, an (from left to right) and the 
digits of B as b1, b2, ... , bn (from left to right).  C = A ^^ B will consist of the digits c1, 
c2, ... , cn (from left to right), where ci = (ai ^ bi) % 10, where ^ is the usual bitwise XOR 
operator (see notes for exact definition) and x % y is the remainder of x divided by y.  If C 
happens to have any extra leading zeroes, they are ignored.

For example, 8765 ^^ 2309 = 462 (c1 = (8 ^ 2) % 10 = 10 % 10 = 0, c2 = (7 ^ 3) % 10 = 4 % 10 = 4, 
c3 = (6 ^ 0) % 10 = 6 % 10 = 6, c4 = (5 ^ 9) % 10 = 12 % 10 = 2), and 5 ^^ 123 = 126 ("5" is 
prepended with two leading zeros to become "005").

When multiple ^^ operations occur in an expression, they must be evaluated from left to right.  
For example, A ^^ B ^^ C means (A ^^ B) ^^ C.

You are given an int N.  Return the value of N ^^ (N - 1) ^^ (N - 2) ^^ �c ^^ 1.

DEFINITION
Class:DoubleXor
Method:calculate
Parameters:int
Returns:int
Method signature:int calculate(int N)


NOTES
-If a and b are single bits then a ^ b is defined as (a + b) % 2. For two integers, A and B, in 
order to calculate A ^ B, they need to be represented in binary: A = (an...a1)2, B = (bn...b1)2 
(if the lengths of their representations are different, the shorter one is prepended with the 
necessary number of leading zeroes). Then A ^ B = C = (cn...c1)2, where ci = ai ^ bi. For example, 
10 ^ 3 = (1010)2 ^ (0011)2 = (1001)2 = 9.


CONSTRAINTS
-N will be between 1 and 1,000,000, inclusive.


EXAMPLES

0)
1

Returns: 1

This is simply 1.

1)
2

Returns: 3

2^^1=3

2)
7

Returns: 0

7^^6^^5^^4^^3^^2^^1=0

3)
10

Returns: 11

4)
102

Returns: 103



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