#include <string.h>
#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <memory>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;

constexpr int mod = 998244353;

long long fac[200005], finv[200005], inv[200005];

void COMinit() {
    fac[0] = fac[1] = finv[0] = finv[1] = inv[1] = 1;
    for (int i = 2; i < 200005; i++) {
        fac[i] = fac[i - 1] * i % mod;
        inv[i] = mod - inv[mod % i] * (mod / i) % mod;
        finv[i] = finv[i - 1] * inv[i] % mod;
    }
}

long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod;
}

long long choose(int n,int k) {
    if(n < 0 || k < 0) return 0;
    if(n == 0) return 1;
    return COM(n+k-1,k-1);
}

void mpl(int &x,int y) {
    x += y;
    if(x >= mod) x -= mod;
}

int dp[550][550];

int main() {
    COMinit();
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<int>a(n);
    for(int i = 0; i < n; i++) {
        cin >> a[i];
    }
    dp[0][0] = 1;
    int res = 0;
    for(int i = 0; i < n; i++) {
        if(res == 0) {
            dp[i+1][0] = 1;
            res += a[i];
            continue;
        }
        for(int j = 0; j <= res; j++) {
            mpl(dp[i+1][j],dp[i][j]);
            for(int k = 1; k < a[i]; k++) {
                mpl(dp[i+1][j+k],dp[i][j]*choose(k,res-j)%mod);
            }
            if(a[i]) {
                for(int k = j; k < res; k++) {
                    mpl(dp[i+1][k+a[i]],dp[i][j]*choose(a[i]-1,k-j+1)%mod);
                }
            }
        }
        res += a[i];
    }
    int ans = 0;
    for(int i = 0; i <= 500; i++) {
        mpl(ans,dp[n][i]);
    }
    cout << ans << "\n";
}