[백준] P2217

import java.util.Arrays;
import java.util.Scanner;

public class P2217 {
	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt(), a[] = new int[n], max = 0;
		for(int i = 0; i < n; i ++) a[i] = sc.nextInt();
		Arrays.sort(a);
		for(int i = a.length - 1; i >= 0; i--) {
			max = Math.max(max, a[i] * (a.length - i));
		}
		System.out.println(max);
		sc.close();
	}
}