#include <bits/stdc++.h>

#include <atcoder/all>
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define FAST_IO                \
  ios::sync_with_stdio(false); \
  cin.tie(0);
const i64 INF = 1001001001001001001;
using Modint = atcoder::static_modint<998244353>;

vector<vector<Modint>> enumFIF(int n) {
  vector fif(2, vector(n + 1, Modint(0)));
  fif[0][0] = 1;
  for (auto i : views::iota(1, n + 1)) {
    fif[0][i] = fif[0][i - 1] * i;
  }
  fif[1][n] = fif[0][n].inv();
  for (auto i = n; i > 0; i--) {
    fif[1][i - 1] = fif[1][i] * i;
  }
  return fif;
}

Modint conv(int n, int r, vector<vector<Modint>>& fif) {
  return fif[0][n] * fif[1][r] * fif[1][n - r];
}



int main() {
  FAST_IO


  int N;
  cin >> N;
  vector<Modint> A(N);
  for (int i = 0; i < N; i++) {
    i64 x;
    cin >> x;
    A[i] = x;
  }



  Modint ans = 0;
  auto fif = enumFIF(N * 2);
  for (int i = 0; i < N; i++) {
    Modint x = conv((N - 1) * 2 - i, N - 1 - i, fif);
    Modint y = conv((N - 1) * 2 - i, N - 1 - i - 1, fif);
    ans += A[i] * (x - y);
  }


  cout << ans.val() << endl;
}