Problems
Invert a bit
Invert a bit
Two integers а and k are given. Print number that is obtained from а by inverting the k-th bit.
Input data
One line contains two integers a and k (0 ≤ a ≤ 10^9
).
Output data
Print the number a with k-th bit inverted.
Examples
Input example #1
5 1
Output example #1
7