175. Encoding

time limit per test: 0.25 sec.
memory limit per test: 4096 KB
input: standard
output: standard



Let phi(W) is the result of encoding for algorithm:
1. If the length of W is 1 then phi(W) is W;
2. Let coded word is W = w1w2...wN and K = N / 2 (rounded down);
3. phi(W) = phi(wNwN-1...wK+1) + phi(wKwK-1...w1).
For example, phi('Ok') = 'kO', phi('abcd') = 'cdab'.
Your task is to find position of letter wq in encoded word phi(W).

Input
Given integers N, q (1 <= N <= 10^9; 1<= q <= N), where N is the length of word W.

Output
Write position of letter wq in encoded word phi(W).

Sample test(s)

Input
9 4 

Output
8 
  
  
Author:Michael R. Mirzayanov 
Resource:Saratov ST team Spring Contest #1 
Date:18.05.2003