#include <bits/stdc++.h> #include<atcoder/all> #define double long double using namespace std; int size(int number){ string numstr=to_string(number); return numstr.size(); } constexpr int MOD=998244353; signed main(void){ int N; cin>>N; vector<int>A(N); for(int i=0;i<N;++i){ cin>>A.at(i); } vector<map<int,int>>dp(N); dp.at(0)[A.at(0)]=1; for(int i=1;i<N;++i){ auto back=dp.at(i-1); dp.at(i)=move(dp.at(i-1)); if(back.find(A.at(i)-1)!=back.end()){ dp.at(i)[A.at(i)]+=back[A.at(i)-1]+1; dp.at(i)[A.at(i)]%=MOD; }else{ dp.at(i)[A.at(i)]+=1; dp.at(i)[A.at(i)]%=MOD; } } int ans=0; for(auto e:dp.at(N-1)){ ans+=e.second; ans%=MOD; } cout<<(ans-A.size())%MOD<<endl; }