lib C
  fun strtoll(s : UInt8*, p : UInt8**, b : Int32) : Int64
end

class String
  def to_i64
    C.strtoll(self, nil, 10)
  end
end

a, b, c, d = read_line.split.map(&.to_i64)
if a == c || b == d || (a - c).abs + (b - d).abs <= 3
  puts 1
else
  puts 2
end