import java.util.*

fun main(args: Array<String>) {
  val sc = Scanner(System.`in`)
  val n = sc.nextInt()
  val w = (1..n).map { sc.next() }

  val ans = b(w)
  println(ans)
}

private fun b(w: List<String>): String {
  val set = mutableSetOf<String>()
  var preLast = w.get(0).first()
  for (wi in w) {
    if (set.contains(wi)) return "No"
    if (wi.first() != preLast) return "No"
    set.add(wi)
    preLast = wi.last()
  }
  return "Yes"
}
