program name
    implicit none
    integer(4):: h,w,cnt
    integer(4):: a_cnt(ichar('a'):ichar('z'))
    character(:),allocatable:: a
    integer(4):: i,j,d
    logical :: b

    read*, h,w
    allocate(character(w):: a)
    a_cnt(:) = 0
    do i=1,h
        read*, a(:)
        do j=1,w
            a_cnt(ichar(a(j:j))) = a_cnt(ichar(a(j:j))) + 1
        end do
    end do

    a_cnt(:) = mod(a_cnt(:),4)
    
    if (mod(w,2) == 0 .and. mod(h,2) == 0) then
        b = sum(a_cnt) == 0
    else if(mod(w,2) /= 0 .and. mod(h,2) /= 0) then
        b = sum(mod(a_cnt,2)) <= 1 .and. sum(a_cnt) <= w+h-1
    else
        if (mod(w,2) == 0) then
            d = w
        else
            d = h
        end if

        b = sum(mod(a_cnt,2)) == 0 .and. sum(a_cnt) <= d
    end if

    if (b) then
        print*, 'Yes'
    else
        print*, 'No'
    end if
end program name