mod=998244353
dp={}
ans=0
N=int(input())
A=list(map(int,input().split()))
for i in range(N-1,-1,-1):
	if not A[i] in dp:
		dp[A[i]]=0
	if A[i]+1 in dp:
		ans=(ans+dp[A[i]+1])%mod
		dp[A[i]]+=dp[A[i]+1]
	dp[A[i]]=(dp[A[i]]+1)%mod
print(ans)