/**
 * This code completion exercise aims to find the common letters across the names of different actors or actresses.
 *
 * @param actor A dictionary containing the names of actors/actresses as keys and their corresponding movies as values.
 * @return A string representing the common letters found in the names of all actors/actresses.
 */
fun findCommonLetters(actor: Map<String, String>): String {

    var commonLetters = actor.values.first().toSet()

    for (value in actor.values) {
        commonLetters = commonLetters.intersect(value.toSet())
    }

    val commonLettersStr = commonLetters.sorted().joinToString("")

    return commonLettersStr
}
/**
 * This code completion exercise aims to find the common letters across the names of different actors or actresses.
 *
 * @param actor A dictionary containing the names of actors/actresses as keys and their corresponding movies as values.
 * @return A string representing the common letters found in the names of all actors/actresses.
 */
fun findCommonLetters(actor: Map<String, String>): String {
/**
 * This code completion exercise aims to find the common letters across the names of different actors or actresses.
 *
 * @param actor A dictionary containing the names of actors/actresses as keys and their corresponding movies as values.
 * @return A string representing the common letters found in the names of all actors/actresses.
 */
fun findCommonLetters(actor: Map<String, String>): String {

    var commonLetters = actor.values.first().toSet()

    for (value in actor.values) {
        commonLetters = commonLetters.intersect(value.toSet())
    }

    val commonLettersStr = commonLetters.sorted().joinToString("")

    return commonLettersStr
}