#include<bits/stdc++.h>
#define int long long
const int N = 1000 + 5 , mod = 998244353 ; 
using namespace std;

void add(int& a , int b) {
    if ((a += b) >= mod) a -= mod ; 
}

int c[N][N] ; 
int C(int n , int m) {
    if (m < 0 || n < m) return 0 ; 
    return c[n][m] ; 
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);

    for (int i = 0 ; i < N ; ++ i) {
        for (int j = 0 ; j <= i ; ++ j) {
            if (i == 0) c[i][j] = j == 0 ; 
            else {
                c[i][j] = c[i - 1][j] ; 
                if (j) add(c[i][j] , c[i - 1][j - 1]) ; 
            }
        }
    } 
    
    int n ; 
    cin >> n ; 
    vector c(n + 1 , 0ll) ; 
    for (int i = 1 ; i <= n ; ++ i) cin >> c[i] ; 

    constexpr int m = 503 ; 
    vector f(m + 1 , 0ll) ; 
    f[0] = 1 ; 
    for (int i = 1 ; i <= n ; ++ i) if (c[i]) {
        vector g(m + 1 , 0ll) ; 
        for (int j = 0 ; j <= m ; ++ j) if (f[j]) {
            add(g[j + c[i]] , f[j]) ; 
            for (int w = 0 ; w < c[i] ; ++ w) {
                for (int jj = 1 ; jj <= j ; ++ jj) {
                    int p = j - jj , q = c[i] - 1 - w ; 
                    add(g[jj + w] , f[j] * C(p + q , q) % mod) ; 
                }
            }
        }
        f = g ; 
        // cout << "I : " << i << '\n' ; 
        // for (int i = 0 ; i <= m ; ++ i) cout << f[i] << ' ' ; cout << '\n' ; 
    }
    // return 0 ; 
    int res = 0 ; 
    for (int i = 0 ; i <= m ; ++ i) 
        add(res , f[i]) ; 
    cout << res << '\n' ; 
    return 0;
}