program palindrome_phobia
  implicit none
  character(100) :: s
  integer :: h, w, n(26), i, j, g(3)
  logical :: f
  read(*,*) h, w
  n = 0
  do i = 1, h
    read(*,*) s
    s = trim(adjustl(s))
    do j = 1, w
      n(ichar(s(j:j))-96) = n(ichar(s(j:j))-96)+1
    end do
  end do
  g(1) = mod(h,2)*mod(w,2)
  g(2) = mod(w,2)*(h/2)+mod(h,2)*(w/2)
  g(3) = (h/2)*(w/2)
  do while (g(1).gt.0)
    do i = 1, 26
      if (mod(n(i),2).eq.1) then
        n(i) = n(i)-1
        exit
      end if
    end do
    g(1) = g(1)-1
  end do
  do while (g(2).gt.0)
    f = .false.
    do i = 1, 26
      if (mod(n(i),4).eq.2) then
        n(i) = n(i)-2
        f = .true.
        exit
      end if
    end do
    if (f) then
      g(2) = g(2)-1
      cycle
    end if
    if (g(1).eq.1) exit
    do i = 1, 26
      if (n(i).eq.0) cycle
      if (mod(n(i),4).eq.0) then
        n(i) = n(i)-4
        exit
      end if
    end do
    g(2) = g(2)-2
  end do
  do while (g(3).gt.0)
    do i = 1, 26
      if (n(i).eq.0) cycle
      if (mod(n(i),4).eq.0) then
        n(i) = n(i)-4
        exit
      end if
    end do
    g(3) = g(3)-1
  end do
  if (sum(n).eq.0) then
    write(*,'(a)') "Yes"
  else
    write(*,'(a)') "No"
  end if
  stop
end program palindrome_phobia