#include <bits/stdc++.h>
using namespace std;
const int Mod=998244353;
int n,g[510][510],f[510][510],a[510];
int main() {
    
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin>>n;
    for (int i=1;i<=n;i++) cin>>a[i];
    g[0][0]=1;
    for (int i=1;i<=n;i++) {
        g[i][0]=1;
        for (int j=1;j<=n;j++) 
          for (int k=0;k<=j;k++)
            g[i][j]+=g[i-1][j-k],g[i][j]%=Mod;
    }
    int s=0;
    f[0][0]=1;
    for (int i=1;i<=n;i++) {
        for (int j=0;j<=s;j++) {
            for (int k=j;k<s;k++) 
              for (int t=0;t<a[i];t++)
                f[i][k+1+t]=(f[i][k+1+t]+1LL*f[i-1][j]*g[k-j+1][t]%Mod)%Mod;
            f[i][j]+=f[i-1][j];f[i][j]%=Mod;
        }
        s+=a[i];
    }
    int ans=0;
    for (int i=0;i<s;i++) ans=(ans+f[n][i])%Mod; 
      cout<<ans;
    return 0;
          
}