## https://yukicoder.me/problems/no/2055

MOD = 998244353


def main():
    N = int(input())
    A = list(map(int, input().split()))

    one_map = {}
    two_map = {}
    for a in A:
        b = a - 1
        c = 0
        if b in one_map:
            c += one_map[b]
            c %= MOD
        if b in two_map:
            c += two_map[b]
            c %= MOD

        if a not in two_map:
            two_map[a] = 0
        two_map[a] += c
        two_map[a] %= MOD

        if a not in one_map:
            one_map[a] = 0
        one_map[a] += 1

    answer = 0
    for value in two_map.values():
        answer += value
        answer %= MOD
    print(answer)



if __name__ == "__main__":
    main()