use std::io::Read;

fn main() {
	let mut s = String::new();
	std::io::stdin().read_to_string(&mut s).ok();
	let n: Vec<usize> = s.split_whitespace().flat_map(str::parse).collect();
	let (mut c, mut d) = (0, 0);
	for i in 0..n[0] {
		d += 1;
		if n[i + 1] == 0 {
			c += d * (n[0] - i);
			d = 0;
		}
	}
	println!("{c}")
}