N = io.read("*n")
W1 = {}
W2 = {}
for i=1, N do
    w=io.read()
    if W1[w] == nil then
        W1[w] = 1
    else
        W1[w] = W1[w] + 1
    end
    W2[i] = w
end

for key, _ in pairs(W1) do
    if W1[key] ~= 1 then
        print("No")
        return
    end
end

for i=1, N-1 do
    if W2[i]:sub(#W2[i],#W2[i]) ~= W2[i+1]:sub(1,1) then
        print("No")
        return
    end
end

print("Yes")