#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 998244353;

int main() {
    int N;
    cin >> N;
    vector<ll> A(N);
    for (int i = 0; i < N; i++) {
        cin >> A[i];
    }

    ll ans = 0;
    for (int i = 0; i < N; i++) {
        (ans += A[i] * (i + 2)) %= MOD;
    }

    N += MOD - 3;
    ll bi = 2;
    while (N) {
        if (N % 2 == 1)
            (ans *= bi) %= MOD;
        (bi *= bi) %= MOD;
        N /= 2;
    }
    cout << ans << endl;
}