import java.util.*

fun main(args: Array<String>) {
    Scanner(System.`in`).use {
        val n = it.nextInt()
        var s: Char? = null
        val ww= mutableListOf<String>()
        for (i in 0 until n) {
            val w = it.next()
            if (s == null || s == w[0]) {
                for(www in ww){
                    if(www==w){
                        println("No")
                        return
                    }
                }
                s = w.last()
                ww.add(w)
            } else {
                println("No")
                return
            }
        }
        println("Yes")
    }
}
