MOD = 998244353
P = 999630629

n = int(input())
a = list(map(int, input().split()))

sum_b = 0
for num in a:
    sum_b += num % P
    if sum_b >= MOD:  # To prevent overflow, but we can mod sum_b at the end
        sum_b -= MOD

sum_b %= MOD  # This ensures sum_b is within MOD to compute (sum_b * pow(2, n-1, MOD)) % MOD

pow_2 = pow(2, n-1, MOD)
ans = (sum_b * pow_2) % MOD
print(ans)