import java.util.*
 
fun main(args: Array<String>) {
    val cin = Scanner(System.`in`)
    val N : Int = cin.nextInt()
    var Ws = ArrayList<String>()
    for (i in 1..N) {
        Ws.add(cin.next())
    }
    var prev = Ws[0][Ws[0].lastIndex]
    var used = mutableMapOf<String, Boolean>()
    used[Ws[0]] = true
    var ans : Boolean = true
    for (i in 1..N-1) {
        if (Ws[i][0] != prev || used[Ws[i]] != null) {
            ans = false
        }
        used[Ws[i]] = true
        prev = Ws[i][Ws[i].lastIndex]
    }
    if (ans) {
        println("Yes")
    } else {
        println("No")
    }
}