#include <bits/stdc++.h>
using namespace std;
using ull=unsigned long long;
using ll=long long;
const ll mod=998244353;
ll dp[510][510];
int n;ll a[510];
ll pw[1010],inv[1010];
ll qpow(ll a,ll b,ll mod){
    ll ans=1;
    while(b){
        if(b&1) ans=ans*a%mod;
        a=a*a%mod;
        b>>=1;
    }
    return ans;
}
void intt(){
    pw[0]=1;
    for(int i=1;i<=1000;i++)    pw[i]=pw[i-1]*i%mod;
    inv[1000]=qpow(pw[1000],mod-2,mod);
    for(int i=999;i>=1;i--)    inv[i]=inv[i+1]*(i+1)%mod;
    inv[0]=1;
}
ll get(int x,int y){
    if(y>x) return 0;
    return pw[x]*inv[y]%mod*inv[x-y]%mod;
}
ll pz[5010];
void solve() {
    cin>>n;
    for(int i=1;i<=n;i++)   cin>>a[i];
    pz[n+1]=1;
    ll sm=0,seg=1;
    for(int i=n;i>=1;i--){
        sm+=a[i];seg=seg*inv[a[i]]%mod;
        pz[i]=pw[sm]*seg%mod;
    }
    ll ans=0;
    dp[0][0]=1;int pre=0;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=pre-1;j++){
            ll t=dp[i-1][j]*(get(pre+a[i],pre)-get(pre+a[i]-j,pre-j))%mod*pz[i+1]%mod*get(sm,pre+a[i])%mod;
            ans=((ans+t)%mod+mod)%mod;
        }
        pre+=a[i];
        for(int j=0;j<=pre;j++){
            dp[i][j]=dp[i-1][j];
            ll t=0;
            if(a[i]==0) continue;
            for(int k=0;k<j;k++){
                ll sum=0;
                int le=(pre-a[i]>=j?0:j-(pre-a[i]));
                //if(k==0&&i==2&&j==2)    cout<<le<<'\n';
                int re=a[i]-1;
                for(int z=le;z<=re;z++){
                    dp[i][j]=(dp[i][j]+dp[i-1][k]*get(j-k-1,z)%mod)%mod;
                }
            }
        }
    }
    cout<<((pz[1]-ans)%mod+mod)%mod;
}
int main() {
    ios::sync_with_stdio(0),cin.tie(0);
    int _ = 1;
    intt();
    while(_--) solve();
    return 0;
}