
object Main {
    def solve(used : Set[String], ws : List[String]) : Unit = {
        ws match {
            case Nil => println("Yes")
            case w::Nil => 
                if (used contains w) println("No") else println("Yes")
            case w1::w2::ws => {
                if (w1(w1.length - 1) == w2(0) && !(used contains w1))
                    solve(used + w1, w2::ws)
                else
                    println("No")
            }
        }
    }
    def main(args: Array[String]) = {
        val sc = new java.util.Scanner(System.in)
        val n = sc.nextInt
        val ws = List.fill(n)(sc.next)
        solve(Set(), ws)
    }
}