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//2)*(w//2)

while g1>0 do
    local checker=false
    for k,v in pairs(map) do
        if v%4==1 or v%4==3 then
            map[k]=map[k]-1
            g1=g1-1
            checker=true
        end
    end
    if not checker then
        print("No")
        return
    end
end

while g2>0 do
    local checker=false
    for k,v in pairs(map) do
        if v%4==2 then
            map[k]=map[k]-2
            g2=g2-1
            checker=true
        end
    end
    if not checker then
        print("No")
        return
    end
end

while g4>0 do
    local checker=false
    for k,v in pairs(map) do
        if v%4==0 then
            map[k]=map[k]-4
            g4=g4-1
            checker=true
        end
    end
    if not checker then
        print("No")
        return
    end
end

print("Yes")