import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		String[] sa = br.readLine().split(" ");
		int[] a = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = Integer.parseInt(sa[i]);
		}
		br.close();

		int mod = 998244353;
		Map<Integer, Long> dp = new HashMap<>();
		Map<Integer, Long> val = new HashMap<>();
		for (int i = 0; i < n; i++) {
			long d1 = dp.getOrDefault(a[i], 0L);
			long d2 = dp.getOrDefault(a[i] - 1, 0L);
			long v1 = val.getOrDefault(a[i], 0L);
			long v2 = val.getOrDefault(a[i] - 1, 0L);
			dp.put(a[i], (d1 + d2 + v2) % mod);
			val.put(a[i], v1 + 1);
		}

		long ans = 0;
		for (long v : dp.values()) {
			ans += v;
		}
		ans %= mod;
		System.out.println(ans);
	}
}