#include<bits/stdc++.h>
using namespace std;
constexpr int N=5005;
typedef long long ll;
constexpr ll mod=998244353;
int n,cur,a[N];
ll f[N],g[N],ans;
int main(){
    cin>>n;
    for(int i=1;i<=n;i++) cin>>a[i];
    f[0]=1;
    for(int i=1;i<=n;i++)if(a[i]){
        while(a[i]){
            cur++;
            for(int j=cur;j>=0;j--) g[j+a[i]]=(g[j+a[i]]+f[j])%mod,f[j]=(f[j]+f[j+1])%mod;
            a[i]--;f[0]=0;
        }
        for(int i=0;i<=cur;i++) f[i]=(f[i]+g[i])%mod,g[i]=0;
    }
    ll ans=0;
    for(int j=0;j<=cur;j++) ans+=f[j];
    cout<<ans%mod<<'\n';
}