// 

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

using ll = long long;

#define rep(i, n) for (int i=0; i<(int)(n); ++(i))
#define rep3(i, m, n) for (int i=(m); (i)<(int)(n); ++(i))
#define repr(i, n) for (int i=(int)(n)-1; (i)>=0; --(i))
#define rep3r(i, m, n) for (int i=(int)(n)-1; (i)>=(int)(m); --(i))
#define all(x) (x).begin(), (x).end()

const int INF = (int)(1e9);
const int MAX = (int)(1e5);
const ll mod = 998244353LL;

int main() {
	int n;
	cin >> n;
	vector<int> a(n);
	rep(i, n) cin >> a[i];
	vector<ll> dp(MAX+2);
	rep3(i, a[0], MAX+1) dp[i+1] = (1 + dp[i]) % mod;
	rep3(i, 1, n) {
		vector<ll> ndp(MAX+2);
		rep3(j, a[i], MAX+1) {
			int li = a[i-1], ri = min(j, j-a[i]+a[i-1]);
			if (li > ri) continue;
			ndp[j+1] = ((dp[ri+1]-dp[li]+mod) % mod + ndp[j]) % mod;
		}
		swap(ndp, dp);
	}
	cout << dp[MAX+1] << endl;
	return 0;
}