# Enter your code here. Read input from STDIN. Print output to STDOUT
n, m = gets.strip.split(" ")
n=n.to_i
m=m.to_i
def cuts(n, m)
  min = 0
  count = 0
  if n>1 
    (n-1).times do |i|
      count = 1 + cuts(i+1, m) + cuts(n-i-1, m)
      min==0 || min>count ? min=count : nil
    end
  end
  if m>1  
    (m-1).times do |i|
      count = 1 + cuts(n, i+1) + cuts(n, m-i-1)
      min==0 || min>count ? min=count : nil
    end
  end
  min
end

puts cuts(n, m)