fun main() {
    val builder = StringBuilder()

    readInputLine()
    val pArr = readInputLine().split(" ").map { it.toLong() }

    if (pArr.contains(0L)) {
        builder.appendLine(0)
    } else {
        builder.appendLine(pArr.fold(1L) { acc, l -> root(acc * (l % 9L)) })
    }

    print(builder.toString())
}

fun readInputLine(): String {
    return readLine()!!
}

fun root(a: Long): Long {
    return if (a % 9L != 0L) a % 9L else 9L
}