Being a nonconformist, Volodya is displeased with the current state of things, particularly with the order of natural numbers (natural number is positive integer number). He is determined to rearrange them. But there are too many natural numbers, so Volodya decided to start with the first n. He writes down the following sequence of numbers: firstly all odd integers from 1 to n (in ascending order), then all even integers from 1 to n (also in ascending order). Help our hero to find out which number will stand at the position number k.

Input

The only line of input contains integers n and k (1 ≤ k ≤ n ≤ 1012).

Please, do not use the %lld specifier to read or write 64-bit integers in C++. It is preferred to use the cin, cout streams or the %I64d specifier.

Output

Print the number that will stand at the position number k after Volodya's manipulations.

Examples

Input

10 3


Output

5

Input

7 7


Output

6

Note

In the first sample Volodya's sequence will look like this: {1, 3, 5, 7, 9, 2, 4, 6, 8, 10}. The third place in the sequence is therefore occupied by the number 5.
from __future__ import division
import sys
from collections import namedtuple #x=namedtuple('point','x y')
from math import *
from collections import deque, OrderedDict #append #popleft
from fractions import gcd
from copy import copy ,deepcopy
from collections import Counter #Counter(list)
import re #re.split("[^a-zA-Z]",text)
from decimal import Decimal
# from functools import lru_cache #@lru_cache(maxsize = None)
"""
#reduce(func,list)
#map(func,list)
#filter(func,list)
#xor=lambda x,y :x^y
#sign = lambda x: math.copysign(1, x)
#list.reverse() 
#list.sort() list=sorted(list)
list.sort(key=operator.itemgetter(1,2))
#reverse word word[::-1]
#word.islower()
#word.lower() word.upper()
x = x1 if exp1 else x2
any([false,true])
all([true,false])
"a".isalpha()
"1".isdigit()
int(str,base)
"""


fin=sys.stdin ;fout=sys.stdout 
# fin=open('../in','r') ; fout=open('../out','w')
def readline():
    return fin.readline().strip()
def readstrings():
    return fin.readline().strip().split(' ')
def writeline(value):
    fout.write(str(value))
    fout.write("\n")
def read_integers():
    return [int(x) for x in fin.readline().strip().split(' ')]
def read_integer():
    return int(fin.readline().strip())
def end():
    sys.exit()
def readbig():
    return [Decimal(x) for x in fin.readline().strip().split(' ')]
    

n,k=readbig()
last=Decimal(ceil(n/2)-1)
k=k-1
if k <= last:
    writeline(int(((k+1)*2)-1))
else:
    writeline(int(floor(k-last)*2))