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

#include "atcoder/all"
using namespace atcoder;
using Mint = modint998244353;

int main() {
    int N;
    cin >> N;
    vector<int> A(N);
    map<int, int> mp;
    Mint maine = 1;
    for (auto&& a : A) {
        cin >> a;
        mp[a]++;
        maine *= a;
    }
    Mint ans = 0;
    for (auto&& [a, n] : mp) {
        Mint book = 1;
        for (auto&& b : A) {
            if (b != a)
                book /= (-Mint{a} * Mint{a} + Mint{b} * Mint{b});
            else
                book /= Mint{2} * a;
        }
        ans += book;
    }
    ans *= 2;
    cout << ans.val() << endl;
}