codeforces 318A Even Odds

A. Even Odds

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

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 from1 to n (in ascending order), then all even integers from1 to n (also in ascending order). Help our hero to find out which number will stand at the position numberk.

Input

The only line of input contains integers n andk (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 thecin, 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.

AC:

#include
using namespace std;
int main()
{
    long long n,k;
    cin>>n>>k;
    if(n%2)
    {
        if(k>n/2+1)
            cout<<(k-n/2-1)*2;
        else
            cout<<2*k-1;
    }
    else
    {
        if(k>n/2)
            cout<<(k-n/2)*2;
        else
            cout<<2*k-1;
    }

}