import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		sc.close();

		long ans = (long) n * (n + 1) / 2;
		int cnt = 0;
		for (int i = 0; i < n; i++) {
			if (a[i] == 1) {
				cnt++;
			} else {
				ans -= (long) cnt * (cnt + 1) / 2;
				cnt = 0;
			}
		}
		ans -= (long) cnt * (cnt + 1) / 2;
		System.out.println(ans);
	}
}