#pragma GCC Optimize("Ofast")
#include<bits/stdc++.h>
using namespace std;
#define int long long
const int maxn=505+5,M=1e6+5,mod=998244353;
#define pb push_back
#define pi pair<int,int>
#define fi first
#define se second
inline int read(){
    char ch=getchar();int x=0;bool f=0;
    for(;!isdigit(ch);ch=getchar())if(ch=='-'){f=1;}
    for(;isdigit(ch);ch=getchar())x=(x<<1)+(x<<3)+(ch^48);
    if(f==1)x=-x;
    return x;
}
int n,m,f[maxn][maxn],C[maxn][maxn],a[maxn];
signed main(){
    n=read();
    for(int i=1;i<=n;i++)a[i]=read(),m+=a[i];
    C[0][0]=1;
    for(int i=1;i<=502;i++){
        C[i][0]=1;
        for(int j=1;j<=i;j++){
            C[i][j]=(C[i-1][j]+C[i-1][j-1])%mod;
        }
    }
    f[0][0]=1;int s=0;
    for(int i=0;i<n;i++){
        s+=a[i];
        for(int j=0;j<=m;j++)if(f[i][j]){
            //cout<<f[i][j]<<" "<<i<<" "<<j<<endl;
            if(a[i+1]==0){f[i+1][j]=f[i][j];continue;}
            int p=min(j-s,a[i+1]);
            for(int z=a[i+1]-p;z<=a[i+1];z++){
                for(int l=z;l<=m-j;l++){
                    //cout<<i+1<<" "<<j+l<<" "<<z<<" "<<l<<" "<<a[i]<<endl;
                    if(l==0){
                        f[i+1][j+l]=(f[i+1][j+l]+f[i][j])%mod;
                    }
                    else {
                        f[i+1][j+l]=(f[i+1][j+l]+f[i][j]*C[l-1][z-1])%mod;
                    
                    }
                }
            }
        }
    }
    cout<<f[n][m]<<endl;
}