// Problem   Histogram// Algorithm Stack// Runtime   O(n)// Author    Walter Guttmann// Date      19.06.2003import java.io.*;public class histogram{  static long[] h = new long[1<<18];  static int[] rS = new int[1<<18];  static int[] lS = new int[1<<18];  public static void main(String[] arg) throws Exception  {    StreamTokenizer st = new StreamTokenizer(new BufferedReader(new FileReader("histogram.in")));    while (true)    {      st.nextToken();      int n = (int) st.nval;      if (n == 0) break;      for (int i=0 ; i<n ; i++)      {        st.nextToken();        h[i] = (long) st.nval;      }      h[n] = 0;      long max_area = 0;      int sp = 0;      for (int i=0 ; i<=n ; i++)      {        lS[sp] = i;        while (sp > 0 && h[rS[sp-1]] > h[i])        {          --sp;          max_area = Math.max(max_area, (i-lS[sp])*h[rS[sp]]);        }        rS[sp] = i;        ++sp;      }      System.out.println(max_area);    }  }}