#include <bits/stdc++.h>
using namespace std;
int n, a[1000001], m, c;


int main() {
	cin >> n;
	c = n;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
	}
	for (int i = 1; i <= n; i++) {
		if (a[i] != a[i + 1]) {
			c++;
		}

	}
	cout << c << endl;
	sort(a + 1, a + n + 1);
	for (int i = 1; i <= n; i++) {
		if (a[i] == 1) {
			cout << a[i] << " ";
		}

	}

	return 0;
}