fun main(args: Array<String>) {
    val n = readInputLine().toInt()
    
    val ws = mutableListOf<String>()
    
    var lastChar = '-'
    
    for (i in 0 until n) {
        val w = readInputLine()
        if (ws.contains(w)) {
            println("No")
            return
        }
        if (i != 0 && w.get(0) != lastChar) {
            println("No")
            return
        }
        
        lastChar = w.get(w.lastIndex)
        ws.add(w)
    }

    println("Yes")
}
 
fun readInputLine(): String {
    return readLine()!!
}
