#include <bits/stdc++.h>
using namespace std;
const long long mod = 998244353;
long long po[1000006];
long long sr[1000006];
long long a[1000006];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  po[0] = 1;
  sr[0] = 1;
  for (int i = 1; i <= 1000002; i++) {
    po[i] = po[i - 1] * 2;
    po[i] %= mod;
  }
  sr[1] = 3;
  for (int i = 2; i <= 1000002; i++) {
    sr[i] = ((i + 2) * po[i - 1]) % mod;
  }
  long long n;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i];
  int pos = 0;
  long long ret = 0;
  for (int i = n - 1; i >= 0; i--) {
    long long co = sr[pos++];
    long long temp = (co * a[i]) % mod;
    ret += temp;
    ret %= mod;
  }
  cout << ret << endl;
}
