#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
#define fi first
#define se second
#define pb push_back
#define int ll

const int N=510,MOD=998244353;

int dp[N][N];
int C[N][N];

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    for(int n=0;n<N;n++)
    {
        C[n][0]=C[n][n]=1;
        for(int k=1;k<n;k++)
            C[n][k]=(C[n-1][k-1]+C[n-1][k])%MOD;
    }

    int n;
    cin>>n;
    int len=0;
    dp[0][0]=1;
    for(int i=1;i<=n;i++)
    {
        int cnt;
        cin>>cnt;
        for(int j=0;j<=len;j++){
            for(int k=j;k<len;k++)
                for (int t = 1; t <= cnt; t++) {
                    dp[i][k + t] += dp[i - 1][j] * C[k - j + 1 + t - 1 - 1][t - 1];
                    dp[i][k + t] %= MOD;
                }
            dp[i][j] += dp[i - 1][j];
            dp[i][j] %= MOD;
        }
        len+=cnt;
//        for(int j=0;j<=len;j++)
//            cout<<i<<" "<<j<<" -> "<<dp[i][j]<<"\n";
    }
    cout<<accumulate(dp[n],dp[n]+len+1,0LL)%MOD;
}