output_description: Print the total length of the ray's trajectory.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      N X
attempt: from fractions import gcd
  n,m=map(int,input().split())
  print(3*(n-gcd(n,m))
problem_description: Statement
  
  Snuke is conducting an optical experiment using mirrors and his new invention,
  the rifle of _Mysterious Light_.
  
  Three mirrors of length N are set so that they form an equilateral triangle.
  Let the vertices of the triangle be a, b and c.
  
  Inside the triangle, the rifle is placed at the point p on segment ab such
  that ap = X. (The size of the rifle is negligible.) Now, the rifle is about to
  fire a ray of Mysterious Light in the direction of bc.
  
  The ray of Mysterious Light will travel in a straight line, and will be
  reflected by mirrors, in the same ways as "ordinary" light. There is one major
  difference, though: it will be also reflected by its own trajectory as if it
  is a mirror! When the ray comes back to the rifle, the ray will be absorbed.
  
  The following image shows the ray's trajectory where N = 5 and X = 2.
  
  ![btriangle.png](https://agc001.contest.atcoder.jp/img/agc/001/Gg9pvPKw/btriangle.png)
  
  It can be shown that the ray eventually comes back to the rifle and is
  absorbed, regardless of the values of N and X. Find the total length of the
  ray's trajectory.
samples: [{"input": "5 2", "output": "12\n    \n\nRefer to the image in the Problem Statement section. The total length of the\ntrajectory is 2+3+2+2+1+1+1 = 12."}]