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

#define int long long  

const int mod = 998244353;

int qpow(int a, int b) {
	int res = 1;
	for (; b; b /= 2, a = a * a % mod) {
		if (b % 2) {
			res = res * a % mod;
		}
	}
	return res;
}

int inv(int a) {
	return qpow(a, mod - 2);
}

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

	int n;
	cin >> n;

	int s = 0;
	vector<int> a(n + 1);
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
		s += a[i];
	}

	vector<int> fac(2 * s + 1, 1);
	for (int i = 1; i <= 2 * s; i++) {
		fac[i] = fac[i - 1] * i % mod;
	}

	int ans = fac[2 * s] * inv(fac[s]) % mod * inv(fac[s + 1]) % mod;


	for (int i = 1; i <= n; i++) {
		ans = ans * inv(fac[a[i]]) % mod;
	}

	cout << ans << "\n";

    return 0;
}