program main
  implicit none
  integer*8::x,y,x2,y2
  read *,x,y,x2,y2
  if(x.eq.y.and.x2.eq.y2.and.x.gt.y2) then
     print '(i0)', MAX(x,y)+1
  else
     print '(i0)', MAX(x,y)
  end if
end program main