import scala.collection.mutable.ListBuffer

object Main extends App {
  import scala.io.StdIn.readLine

  val n = readLine().toInt
  var list : ListBuffer[String] = ListBuffer.empty[String]
  var end : Char = '\0'
  var result = "Yes"
  for (i <- 1 to n) {
    var str = readLine()
    var start = str.charAt(0)
    if (i == 1) end = str.charAt(0)

    if (start != end || list.contains(str)) {
      result = "No"
    }

    list += str
    end = str.charAt(str.length - 1)
  }

  print(result)

}
