Vaqt limiti: 1 sekund
Xotira limiti: 64 MB
In digital
computer programming, a bitwise operation operates on one or
more bit patterns or binary numerals at the level of their
individual bits. It is a fast, primitive action directly supported by the processor,
and is used to manipulate values for comparisons and calculations.
On simple
low-cost processors, typically, bitwise operations are substantially faster
than division, several times faster than multiplication, and sometimes
significantly faster than addition. While modern processors usually perform
addition and multiplication just as fast as bitwise operations due to their
longer instruction pipelines and other architecturaldesign
choices, bitwise operations do commonly use less power because of the reduced
use of resources.
A bitwise OR takes
two bit patterns of equal length and performs the logical inclusive OR operation on
each pair of corresponding bits. The result in each position is 1 if the first
bit is 1 or the second bit is 1 or both bits
are 1; otherwise, the result is 0. For example:
0101 (decimal 5)
OR 0011 (decimal 3)
=
0111 (decimal 7)
The bitwise OR may be
used to set the selected bits to 1. For example, it can be used for setting a
specific bit (or flag) in a register, where each bit represents an individual Boolean state. Thus,
0010 (decimal 2) can be considered a set of four flags, where the first, third,
and fourth flags are clear (0) and the second flag is set (1). The fourth flag
may be set by performing a bitwise OR between this value and a bit pattern with
only the fourth bit set:
0010 (decimal 2)
OR 1000 (decimal 8)
=
1010 (decimal 10)
This technique is an
efficient way to store a number of Boolean values using as little memory as
possible.
In this task you
are given two numbers L and R. You should calculate bitwise OR operation
of numbers from L to R inclusive.
Input
In the first
line given integer numbers L and R(1≤L≤R≤10^{18}).
Output
Output the
answer to the problem.
Examples
№ |
Input |
Output |
1 |
4 6 |
7 |
2 |
10 10 |
10 |
2015 yil Dasturlash bo'yicha Tatu va uning filiallari talabalari o'rtasida jamoaviy olimpiada. Final. Urgench 21-23 aprel.