import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;

public class Back_2217 {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.parseInt(br.readLine());
        int arr[] = new int[N];

        for (int i = 0; i < N; i++) {
            arr[i] = Integer.parseInt(br.readLine());
        }

        Arrays.sort(arr);

        int max = Integer.MIN_VALUE;

        for (int i = 0; i < N; i++) {
            max = Math.max(max, arr[i] * (N - i));
        }
        System.out.println(max);
        br.close();
    }

}