D. Plus and xor
time limit per test
0.5 second
memory limit per test
256 megabytes
standard input
standard output

Bitwise exclusive OR (or bitwise addition modulo two) is a binary operation which is equivalent to applying logical exclusive OR to every pair of bits located on the same positions in binary notation of operands. In other words, a binary digit of the result is equal to 1 if and only if bits on the respective positions in the operands are different.

For example, if X = 10910 = 11011012, Y = 4110 = 1010012, then:

X xor Y  =  6810  =  10001002.

Write a program, which takes two non-negative integers A and B as an input and finds two non-negative integers X and Y, which satisfy the following conditions:

  • A = X + Y
  • B  =  X xor Y, where xor is bitwise exclusive or.
  • X is the smallest number among all numbers for which the first two conditions are true.

The first line contains integer number A and the second line contains integer number B (0 ≤ A, B ≤ 264 - 1).


The only output line should contain two integer non-negative numbers X and Y. Print the only number -1 if there is no answer.

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