program prob6
    implicit none
    integer::H, W, i, j, tmp
    character(len=100)::S
    integer::c(26)
    read(*,*) H, W
    c = 0
    do i = 1, H
        read(*,*) S
        do j = 1, W
            tmp = ichar(S(j:j)) - ichar('a') + 1
            c(tmp) = c(tmp) + 1
        end do
    end do
    if(mod(H*W,2) == 0) then
    	tmp = 0
        do i = 1, 26
            if(mod(c(i),2) == 1) then
                write(*,'(a)') "No"
                stop
            else if(c(i) > 0) then
            	tmp = tmp + 1
            end if
        end do
        if(mod(tmp,2) == 0) then
        	write(*,'(a)') "No"
         	stop
        end if
    else
        tmp = 0
        do i = 1, 26
            if(mod(c(i),2) == 1) then
                tmp = tmp + 1
            end if
        end do
        if(tmp /= 1) then
            write(*,'(a)') "No"
        end if
    end if
    write(*,'(a)') "Yes"
    stop
end program