Maximum XOR

You are given two integers L and R representing the bounds of a range. Your task is to find the maximum value of \(A \oplus B\) where \(A\) and \(B\) are integers that lie in the range \([L, R]\) (inclusive).

The bitwise XOR operation (denoted by \(\oplus\)) between two numbers gives a result where each bit is 1 if the corresponding bits of the two numbers differ and 0 if they are the same.

For example, if \(L = 1\) and \(R = 10\), one of the pairs that gives the maximum XOR is \(A = 5\) and \(B = 10\), and \(5 \oplus 10 = 15\). Your program should compute this maximum value for any given valid input.

inputFormat

The input consists of a single line with two space-separated integers, L and R, where \(L \leq R\). These represent the lower and upper bounds of the range respectively.

outputFormat

Output a single integer, which is the maximum result of the bitwise XOR \(A \oplus B\) for all pairs where \(L \leq A, B \leq R\).

1 10

15