#include <stdio.h>

int main()
{
	int i, N, P[300001];
	scanf("%d", &N);
	for (i = 1; i <= N; i++) scanf("%d", &(P[i]));
	
	int k = 0, l, r, m, dp[300001] = {}, prev[300001], ans[2][300001];
	for (i = 1; i <= N; i++) {
		l = 0;
		r = k;
		while (l < r) {
			m = (l + r + 1) / 2;
			if (P[dp[m]] > P[i]) r = m - 1;
			else l = m;
		}
		if (l == k) k++;
		prev[i] = dp[l];
		dp[l+1] = i;
	}
	for (i = dp[k]; i > 0; i = prev[i]) ans[0][k--] = P[i];

	int j;
	for (i = N, k = 0; i >= 1; i--) {
		l = 0;
		r = k;
		while (l < r) {
			m = (l + r + 1) / 2;
			if (P[dp[m]] < P[i]) r = m - 1;
			else l = m;
		}
		if (l == k) k++;
		prev[i] = dp[l];
		dp[l+1] = i;
	}
	for (i = dp[k], j = 1; i > 0; i = prev[i]) ans[1][j++] = P[i];
	
	for (i = 1, j = 0; i <= k; i++) if (ans[0][i] == ans[1][i]) j++;
	printf("%d\n", j);
	for (i = 1; i <= k; i++) if (ans[0][i] == ans[1][i]) printf("%d ", ans[0][i]);
	printf("\n");
	fflush(stdout);
	return 0;
}