import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int a[] = new int[n + 1];
		long sum = 0;
		for(int i = 1; i <= n; i++) a[i] = sc.nextInt();
		for(int i = 1; i <= n; i++){
			for(int j = 1; j <= n; j++){
				sum += Math.pow(a[i],a[j]);
			}
		}
		System.out.println(sum);
	}
}