Problem:
Score : 900 points

Problem Statement

Nukes has an integer that can be represented as the bitwise OR of one or more integers between A and B (inclusive).
How many possible candidates of the value of Nukes's integer there are?

Constraints

1 ≤ A ≤ B < 2^{60}

A and B are integers.

Input

The input is given from Standard Input in the following format:

A
B

Output

Print the number of possible candidates of the value of Nukes's integer.

Sample Input 1

7
9

Sample Output 1

4

In this case, A=7 and B=9. There are four integers that can be represented as the bitwise OR of a non-empty subset of {7, 8, 9}: 7, 8, 9 and 15.

Sample Input 2

65
98

Sample Output 2

63

Sample Input 3

271828182845904523
314159265358979323

Sample Output 3

68833183630578410

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

a=int(input())
b=int(input())
if a==b:
  print(1)
  exit()
abin=bin(a)[2:]
bbin=bin(b)[2:]
la=len(abin)
lb=len(bbin)
if la==lb:
  while abin[0]==bbin[0]:
    abin=abin[1:]
    bbin=bbin[1:]
  while len(abin)>1 and abin[0]=="0":
    abin=abin[1:]
cbin=bbin[1:]
while len(cbin)>1 and cbin[0]=="0":
  cbin=cbin[1:]
c=2**(len(cbin))-1
a=int(abin,2)
b=int(bbin,2)
lb=len(bbin)
lbnd=2**(lb-1)+c
hbnd=2**(lb-1)+a
if lbnd>=hbnd:
  print(2**lb-a)
else:
  print(2**(lb-1)-a+lbnd-a+1)