import sys, random input = lambda : sys.stdin.readline().rstrip() write = lambda x: sys.stdout.write(x+"\n"); writef = lambda x: print("{:.12f}".format(x)) debug = lambda x: sys.stderr.write(x+"\n") YES="Yes"; NO="No"; pans = lambda v: print(YES if v else NO); INF=10**18 LI = lambda : list(map(int, input().split())); II=lambda : int(input()) def debug(_l_): for s in _l_.split(): print(f"{s}={eval(s)}", end=" ") print() def dlist(*l, fill=0): if len(l)==1: return [fill]*l[0] ll = l[1:] return [dlist(*ll, fill=fill) for _ in range(l[0])] n = int(input()) a = list(map(int, input().split())) M = 998244353 d = {} for v in a: d.setdefault(v,0) d[v] += 1 + d.get(v-1,0) d[v] %= M ans = 0 for k,v in d.items(): ans += v ans %= M print((ans-n)%M)