import java.util.LinkedList
import java.util.PriorityQueue

fun main() {
    val (n, cores) = readln().split(" ").take(2).map { it.toInt() }
    val printouts = ArrayList<Long>(n + 1)
    printouts.add(0)
    val queue = readln().split(" ").map { it.toLong() }.toCollection(LinkedList())
    val procesQueue = PriorityQueue<Long>()
    repeat(cores) { procesQueue.add(0L) }
    while(queue.isNotEmpty()) {
        val current = queue.removeFirst()
        val time = procesQueue.poll() + current
        printouts.add(time)
        procesQueue.add(time)
    }

    println(printouts.sorted().zipWithNext { a, b -> b - a }.max()) // Requires Kotlin 1.7
}