// @EXPECTED_RESULTS@: ACCEPTED, TIME_LIMIT_EXCEEDED
/**
 * This tries to solve the problem by building a trie of all the usernames. It uses recursion, so it might fail on the
 * stack size but should be fine with a max depth of 1000 chars.
 *
 * Same idea, but rather than using fancy datastructures with recursion, a flat approach which basically does the same.
 */
fun main() {
    val words = System.`in`.bufferedReader().lineSequence().drop(1).map { it to 1 }.toList()
    val wordsQueue = mutableListOf(words)
    var usernames = 0
    while (wordsQueue.isNotEmpty()) {
        val current = wordsQueue.removeLast()
        val map = current.groupBy { it.first.first() }
        usernames += map.entries.filter { it.value.size == 1 }.sumOf { it.value.first().second }
        map.values.filter { it.size > 1 }.mapTo(wordsQueue) { list -> list.map { it.first.drop(1) to it.second + 1 } }
    }
    println(usernames)
}