local h,w=io.read("n","n","l")
local map={}
for i=1,h do
    local s=io.read()
    for j=1,w do
        local a=s:sub(j,j)
        map[a]=(map[a] or 0)+1
    end
end

local g1=(h%2)*(w%2)
local g2=(h%2)*(w//2)+(w%2)*(h//2)
local g4=(h*w-2*g2-g1)//4

for k,v in pairs(map) do
    if g1==0 then
        break
    end
    if map[k]%4==1 or map[k]%4==3 then
        while map[k]>0 do
            map[k]=map[k]-1
            g1=g1-1
        end
    end
end

for k,v in pairs(map) do
    if g2==0 then
        break
    end
    if map[k]%4==2 then
        while map[k]>0 do
            map[k]=map[k]-2
            g2=g2-1
        end
    end
end

for k,v in pairs(map) do
    if g1==0 then
        break
    end
    if map[k]%4==0 then
        while map[k]>0 do
            map[k]=map[k]-4
            g4=g4-1
        end
    end
end

local checker=true
for k,v in pairs(map) do
    if v~=0 then
        checker=false
    end
end
print(checker and "Yes" or "No")