
object Main extends App {

  import scala.io.StdIn._

  val n = readLine.trim.toInt
  val words = Array.tabulate(n){_ ⇒ readLine.trim}
  println(
    if (words.distinct.length == words.length && words.foldLeft(Some(words(0).charAt(0)) : Option[Char]){
      case (Some(c), str) if c == str.charAt(0) ⇒ Some(str.charAt(str.length - 1))
      case _ ⇒ None
    }.isDefined) "Yes"
    else "No"
  )
}
