fun main(args: Array<String>) {
    val (h, w) = readLine()?.split(" ")?.map(String::toLong) ?: return
    if (h == 1L || w == 1L) {
        println("1")
        return
    }
    val a1 = w / 2L + w % 2L
    val b1 = h / 2L + h % 2L
    val a2 = w / 2L
    val b2 = h / 2L
    println((a1 * b1 + a2 * b2).toString())
}
