#include <iostream>
#include <string>
#include <algorithm>
#include <utility>
#include <cmath>
#include <cstdlib>
#include <map>
#include <set>
#include <queue>
#include <vector>
#include "testlib.h"
using namespace std;
#define MOD 998244353

long long modinv(long long a, long long mod) {
    long long b = mod, u = 1, v = 0;
    while (b) {
        long long t = a / b;
        a -= t * b; swap(a, b);
        u -= t * v; swap(u, v);
    }
    u %= mod;
    if (u < 0) u += mod;
    return u;
}

int main() {
    long long N = inf.readLong((long long)1, (long long)1000000);
    inf.readEoln();
    vector<long long> A(N);
    A[0] = inf.readLong((long long)1, (long long)1000000);
    for (int i = 1; i < N; i++) {
        inf.readSpace();
        A[i] = inf.readLong((long long)1, (long long)1000000);
    }
    inf.readEoln();
    inf.readEof();
    for (int i = 0; i < N - 1; i++) {
        if (A[i] >= A[i + 1]) cout << -1 << endl;
    }
    long long sum = 0;
    for (long long i = 0; i < N; i++) {
        long long mul = modinv(A[i], MOD);
        for (long long j = 0; j < N; j++) {
            if (i == j) continue;
            mul = mul * modinv(abs(A[j] * A[j] - A[i] * A[i]) % MOD, MOD) % MOD;
        }
        if (i % 2 == 1) mul = MOD - mul;
        sum += mul;
    }
    cout << sum % MOD << endl;
}