// #pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include <bits/stdc++.h>
using namespace std;

#define PB emplace_back
#define int long long
#define ll long long
#define vi vector<int>
#define siz(a) ((int) ((a).size()))
#define rep(i, a, b) for (int i = (a); i <= (b); ++i)
#define per(i, a, b) for (int i = (a); i >= (b); --i)
void print(vi n) {rep(i, 0, siz(n) - 1) cerr << n[i] << " \n"[i == siz(n) - 1];}

const int N = 1000, mod = 998244353;
int a, s[N + 5], f[N + 5], g[N + 5], C[N + 5][N + 5];

signed main() {
	// freopen(".in", "r", stdin);
	// freopen(".out", "w", stdout);
	ios::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);
	rep(i, 0, N) {
		C[i][0] = 1;
		rep(j, 1, i) {
			C[i][j] = (C[i - 1][j] + C[i - 1][j - 1]) % mod;
		}
	}
	cin >> a;
	int x;
	f[0] = 1;
	rep(i, 1, a) {
		cin >> x;
		rep(j, 0, a) g[j] = 0;
		rep(j, 0, a) if(f[j]) {
			(g[j + x] += f[j]) %= mod;
			rep(k, 1, x) rep(p, 0, j - 1) {
				int tmp = 1;
				if(p) tmp = (C[p + 1 + k - 1][p] - C[p + k - 1][p - 1] + mod) % mod;
				// cout << i << ' ' << j - p + x - k << ' ' << C[p + 1 + k - 1][k - 1] << endl;
				(g[j - p + x - k] += f[j] * tmp) %= mod;
			}
		}
		rep(j, 0, a) f[j] = g[j];
		// rep(j, 0, a) cout << f[j] << " \n"[j == a];
	}
	int ans = 0;
	rep(j, 0, a) (ans += f[j]) %= mod;
	cout << ans;
	return cerr << endl << 1.0 * clock() / CLOCKS_PER_SEC << endl, 0;
}