#include<bits/stdc++.h>
#include<unordered_map>
#include<unordered_set>
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
#define debug(a) cout<<a<<'\n'
#define Pll pair<ll,ll>
#define PII pair<int,int>
#define ft first
#define sd second
#define vec vector
#define pushk push_back
#define ump unordered_map
#define pl p<<1
#define pr p<<1|1
using namespace std;
const int N = 5e2 + 10, M = 2e6 + 10, mod = 998244353;
const ll inf = 1e18;
const ld eps = 1e-13;
int mov[4][2] = { {0,1},{1,0},{-1,0},{0,-1} }, dx, dy, _ = 1, __ = 1;
void bout(bool f) {
	if (f)cout << "YES\n";
	else cout << "NO\n";
}
ll n, m, k;
ll dp[N][N],c[N][N],sum[N],a[N];

void ini() {
	c[0][0]=1;
	for(int n=1;n<N;++n){
		for(int i=0;i<=n;++i){
			c[n][i]=(c[n-1][i]+c[n-1][i-1])%mod;
		}
	}
}
void solve() {
	cin>>n;
	for(int i=1;i<=n;++i){
		cin>>a[i];
		sum[i]=sum[i-1]+a[i];
	}
	dp[0][0]=1;
	for(int i=1;i<=n;++i){
		for(int j=1;j<=sum[i]-1;++j){
			for(int x=0;x<=min(sum[i-1]+a[i]-j-1,a[i]-1);++x){
				for(int k=0;k<=j-(a[i]-x);++k){
					dp[i][j]=(dp[i][j]+dp[i-1][k]*c[j-k-1][a[i]-x-1])%mod;
				}
			}
		}
		for(int j=0;j<=sum[i];++j)dp[i][j]=(dp[i][j]+dp[i-1][j])%mod;
	}
	ll ans=0;
	for(int i=0;i<=sum[n]-1;++i)ans=(ans+dp[n][i])%mod;
	ans=(ans%mod+mod)%mod;
	cout<<ans;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
#ifndef ONLINE_JUDGE
	streambuf *cinbp=cin.rdbuf(),*coutbp=cout.rdbuf();
	ifstream fin("in.txt");
	ofstream fout("out.txt");	
	cin.rdbuf(fin.rdbuf());
	cout.rdbuf(fout.rdbuf());
#endif
	//cin >> _;
	__ = _;
	ini();
	while (_--) {
		solve();
	}
	return 0;
}