# Enter your code here. Read input from STDIN. Print output to STDOUT
#! /usr/bin/python

storage={}

def maxmin(m,n):
	if m>n:
		return (m,n)
	else:
		return (n,m)

def cut( m,n ):	
	m,n=maxmin(m,n)	
	if n==1:
		return m-1
	global storage
	if (m,n) in storage:
		return storage[(m,n)]
	half1=m/2
	half2=m-half1
	result=cut(half1,n)+cut(half2,n)+1
	storage[(m,n)]=result
	return result

m,n = map(int,raw_input().strip().split())
print cut(m,n)