import java.util.*

fun main() {
    val builder = StringBuilder()

    readInputLine()

    val aList = readInputLine().split(" ").map { it.toInt() }.sorted()
    val bArr = readInputLine().split(" ").map { it.toInt() }.toIntArray()
    val bListSorted = mutableListOf<Int>()

    var ans = 0L

    for ((i, a) in aList.withIndex()) {
        bListSorted.add(lowerBound(bListSorted, bArr[i]), bArr[i])
        ans += lowerBound(bListSorted, a).toLong()
    }

    builder.appendln(ans)

    print(builder.toString())
}

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

fun <T: Comparable<T>> lowerBound(list: List<T>, value: T): Int {
    return Collections.binarySearch(list, value, { x, y -> if (x >= y) 1 else -1}).inv()
}