#include<bits/stdc++.h>

using namespace std;

const int N = 1e3 + 10, mod = 998244353;

int dp[N][N], n, a[N], c[N][N];

int main()
{
    c[0][0] = 1;
    for (int i = 1; i < N; i++)
    {
        c[i][0] = 1;
        for (int j = 1; j < N; j++)c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % mod;
    }
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++)cin >> a[i];
    dp[0][0] = 1;
    int sum = 0;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 0; j < a[i]; j++)//j=a[i]特判也最好
        {
            for (int k = 1; k <= sum; k++)//k=0特判
            {
                for (int s = 1; s <= k; s++)
                {
                    dp[i][j + s] = (dp[i][j + s] + 1ll * dp[i - 1][k] * c[a[i] - j - 1 + k - s][k - s]) % mod;
                }
            }
        }
        for (int k = 0; k <= sum; k++)
        {
            dp[i][a[i] + k] = (dp[i][a[i] + k] + 1ll * dp[i - 1][k]) % mod;
        }
        sum += a[i];
    }
    int res = 0;
    for (int i = 0; i <= sum; i++)res = (res + dp[n][i]) % mod;
    cout << res;
    return 0;
}