#!/bin/python3

import math

import os

import random

import re

import sys

# Referenced https://www.geeksforgeeks.org/largest-rectangle-under-histogram/

def largestRectangle(heights):

stack = list()

index = 0

largest_rectangle = 0

while index < len(heights):

if (not stack) or (heights[stack[-1]] <= heights[index]):

stack.append(index)

index += 1

else:

top_of_stack = stack.pop()

area = (heights[top_of_stack] *

((index - stack[-1] - 1) if stack else index))

largest_rectangle = max(largest_rectangle, area)

while stack:

top_of_stack = stack.pop()

area = (heights[top_of_stack] *

((index - stack[-1] - 1) if stack else index))

largest_rectangle = max(largest_rectangle, area)

return largest_rectangle

if __name__ == '__main__':

fptr = open(os.environ['OUTPUT_PATH'], 'w')

n = int(input())

h = list(map(int, input().rstrip().split()))

result = largestRectangle(h)

fptr.write(str(result) + '\n')

fptr.close()