import scala.collection.mutable.Stack
import scala.io.StdIn.readLine

object Solution {
  private def carve(heights: Seq[Int]): Int = {
    val extendedHeights = heights :+ 0
    val stack = Stack[Int]()
    var maxArea = 0
    for (i <- extendedHeights.indices) {
      while (stack.nonEmpty && extendedHeights(i) < extendedHeights(stack.top)) {
        val height = extendedHeights(stack.pop())
        val width = if (stack.isEmpty) i else (i - stack.top - 1)
        maxArea = math.max(maxArea, height * width)
      }
      stack.push(i)
    }
    maxArea
  }

  def main(args: Array[String]): Unit = {
    readLine()
    val heights = readLine().trim.split(' ').map(_.toInt).toSeq
    println(carve(heights))
  }
}