
fun main(args : Array<String>) {
    val N = readLine()!!.toInt()
    val W = listOf<String>().toMutableList()
    val alreadySaid = setOf<String>().toMutableSet()

    (1..N).forEach {
        val w = readLine()!!
        W.add(w)
    }

    var ok = true
    var lastChar : Char? = null

    W.forEach {
        if (alreadySaid.contains(it)) {
            ok = false;
            println("No")
            return
        }

        if (lastChar != null && it.get(0) != lastChar) {
            ok = false
            println("No")
            return
        }

        alreadySaid.add(it)
        lastChar = it.get(it.length - 1)
    }


    var answer = if (ok) "Yes" else "No"
    println(answer)
}
