#include<bits/stdc++.h>
#define L(i, j, k) for(int i = (j); i <= (k); ++i)
#define R(i, j, k) for(int i = (j); i >= (k); --i)
#define ll long long
#define vi vector <int>
#define sz(a) ((int) (a).size())
#define me(f, x) memset(f, x, sizeof(f))
#define uint unsigned int
#define ull unsigned long long 
#define i128 __int128
using namespace std; 
const int N = 607, mod = 998244353;
int qpow(int x, int y = mod - 2) {
	int res = 1;
	for(; y; x = (ll) x * x % mod, y >>= 1) if(y & 1) res = (ll) res * x % mod;
	return res;
}
int fac[N], ifac[N], inv[N];
void init(int x) {
	fac[0] = ifac[0] = inv[1] = 1;
	L(i, 2, x) inv[i] = (ll) (mod - mod / i) * inv[mod % i] % mod;
	L(i, 1, x) fac[i] = (ll) fac[i - 1] * i % mod, ifac[i] = (ll) ifac[i - 1] * inv[i] % mod;
} 
int C(int x, int y) {
	return x < y || y < 0 ? 0 : (ll) fac[x] * ifac[y] % mod * ifac[x - y] % mod;
}
inline int sgn(int x) {
	return (x & 1) ? mod - 1 : 1;
}

int n;
int a[N];
int cnt;
int dp[N][N]; 
int ndp[N][N];
int arr[N], tot;
int nxt[N];
int main() {
//	freopen("data.txt", "r", stdin);
	ios :: sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	cin >> n;
	init(555);
	int sum = 0;
	L(t, 1, n) {
		cin >> a[t];
		int go = tot + a[t];
		L(o, 1, a[t]) arr[++tot] = t, nxt[tot] = go;
		sum += a[t];
	}
	
	dp[0][0] = 1;
	R(p, tot, 1) {
		me(ndp, 0);
		L(k, 0, tot) {
			L(j, 0, p) if(dp[k][j]) {
				(ndp[k + 1][j] += dp[k][j]) %= mod;
			}
		}
		L(k, 0, tot) {
			L(j, 0, p) if(ndp[k][j]) {
				(ndp[nxt[k] + 1][j + (nxt[k] + 1 - k)] += ndp[k][j]) %= mod;
			}
		}
		L(k, 0, tot) {
			L(j, 1, p) if(dp[k][j]) {
				(ndp[k][j - 1] += dp[k][j]) %= mod;
			}
		}
		swap(dp, ndp);
	}
	int ans = 0;
	L(i, 0, tot) 
		(ans += dp[i][0]) %= mod;
	cout << ans << '\n';
	return 0;
}