n = int(input())
a = list(map(int, input().split()))
g = {}
dist = [0]*n
for i in range(n):
    ai = a[i]
    if ai in g:
        dist[i] = g[ai]
    if ai+1 in g:
        g[ai+1] += dist[i]+1
    else:
        g[ai+1] = dist[i]+1
    dist[i] %= 998244353
print(sum(dist)%998244353)